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PR middle-end/100504
gcc/c-family/ChangeLog:
* c-attribs.c (handle_target_clones_attribute): Expect a string
argument to target_clone argument.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr100504.c: New test.
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C2X adds digit separators, as in C++. Enable them accordingly in
libcpp and c-lex.c. Some basic tests are added that digit separators
behave as expected for C2X and are properly disabled for C11; further
test coverage is included in the existing g++.dg/cpp1y/digit-sep*.C
tests.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c-family/
* c-lex.c (interpret_float): Handle digit separators for C2X.
libcpp/
* init.c (lang_defaults): Enable digit separators for GNUC2X and
STDC2X.
gcc/testsuite/
* gcc.dg/c11-digit-separators-1.c,
gcc.dg/c2x-digit-separators-1.c, gcc.dg/c2x-digit-separators-2.c:
New tests.
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gcc/ada/ChangeLog:
* gcc-interface/utils.c (def_builtin_1): Use startswith
function instead of strncmp.
gcc/analyzer/ChangeLog:
* sm-file.cc (is_file_using_fn_p): Use startswith
function instead of strncmp.
gcc/ChangeLog:
* builtins.c (is_builtin_name): Use startswith
function instead of strncmp.
* collect2.c (main): Likewise.
(has_lto_section): Likewise.
(scan_libraries): Likewise.
* coverage.c (coverage_checksum_string): Likewise.
(coverage_init): Likewise.
* dwarf2out.c (is_cxx): Likewise.
(gen_compile_unit_die): Likewise.
* gcc-ar.c (main): Likewise.
* gcc.c (init_spec): Likewise.
(read_specs): Likewise.
(execute): Likewise.
(check_live_switch): Likewise.
* genattrtab.c (write_attr_case): Likewise.
(IS_ATTR_GROUP): Likewise.
* gencfn-macros.c (main): Likewise.
* gengtype.c (type_for_name): Likewise.
(gen_rtx_next): Likewise.
(get_file_langdir): Likewise.
(write_local): Likewise.
* genmatch.c (get_operator): Likewise.
(get_operand_type): Likewise.
(expr::gen_transform): Likewise.
* genoutput.c (validate_optab_operands): Likewise.
* incpath.c (add_sysroot_to_chain): Likewise.
* langhooks.c (lang_GNU_C): Likewise.
(lang_GNU_CXX): Likewise.
(lang_GNU_Fortran): Likewise.
(lang_GNU_OBJC): Likewise.
* lto-wrapper.c (run_gcc): Likewise.
* omp-general.c (omp_max_simt_vf): Likewise.
* omp-low.c (omp_runtime_api_call): Likewise.
* opts-common.c (parse_options_from_collect_gcc_options): Likewise.
* read-rtl-function.c (function_reader::read_rtx_operand_r): Likewise.
* real.c (real_from_string): Likewise.
* selftest.c (assert_str_startswith): Likewise.
* timevar.c (timer::validate_phases): Likewise.
* tree.c (get_file_function_name): Likewise.
* ubsan.c (ubsan_use_new_style_p): Likewise.
* varasm.c (default_function_rodata_section): Likewise.
(incorporeal_function_p): Likewise.
(default_section_type_flags): Likewise.
* system.h (startswith): Define startswith.
gcc/c-family/ChangeLog:
* c-ada-spec.c (print_destructor): Use startswith
function instead of strncmp.
(dump_ada_declaration): Likewise.
* c-common.c (disable_builtin_function): Likewise.
(def_builtin_1): Likewise.
* c-format.c (check_tokens): Likewise.
(check_plain): Likewise.
(convert_format_name_to_system_name): Likewise.
gcc/c/ChangeLog:
* c-aux-info.c (affix_data_type): Use startswith
function instead of strncmp.
* c-typeck.c (build_function_call_vec): Likewise.
* gimple-parser.c (c_parser_gimple_parse_bb_spec): Likewise.
gcc/cp/ChangeLog:
* decl.c (duplicate_decls): Use startswith
function instead of strncmp.
(cxx_builtin_function): Likewise.
(omp_declare_variant_finalize_one): Likewise.
(grokfndecl): Likewise.
* error.c (dump_decl_name): Likewise.
* mangle.c (find_decomp_unqualified_name): Likewise.
(write_guarded_var_name): Likewise.
(decl_tls_wrapper_p): Likewise.
* parser.c (cp_parser_simple_type_specifier): Likewise.
(cp_parser_tx_qualifier_opt): Likewise.
* pt.c (template_parm_object_p): Likewise.
(dguide_name_p): Likewise.
gcc/d/ChangeLog:
* d-builtins.cc (do_build_builtin_fn): Use startswith
function instead of strncmp.
* dmd/dinterpret.c (evaluateIfBuiltin): Likewise.
* dmd/dmangle.c: Likewise.
* dmd/hdrgen.c: Likewise.
* dmd/identifier.c (Identifier::toHChars2): Likewise.
gcc/fortran/ChangeLog:
* decl.c (variable_decl): Use startswith
function instead of strncmp.
(gfc_match_end): Likewise.
* gfortran.h (gfc_str_startswith): Likewise.
* module.c (load_omp_udrs): Likewise.
(read_module): Likewise.
* options.c (gfc_handle_runtime_check_option): Likewise.
* primary.c (match_arg_list_function): Likewise.
* trans-decl.c (gfc_get_symbol_decl): Likewise.
* trans-expr.c (gfc_conv_procedure_call): Likewise.
* trans-intrinsic.c (gfc_conv_ieee_arithmetic_function): Likewise.
gcc/go/ChangeLog:
* gofrontend/runtime.cc (Runtime::name_to_code): Use startswith
function instead of strncmp.
gcc/objc/ChangeLog:
* objc-act.c (objc_string_ref_type_p): Use startswith
function instead of strncmp.
* objc-encoding.c (encode_type): Likewise.
* objc-next-runtime-abi-02.c (has_load_impl): Likewise.
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Correctness and performance test programs used during development of
this project may be found in the attachment to:
https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg254210.html
Summary of Purpose
This patch to libgcc/libgcc2.c __divdc3 provides an
opportunity to gain important improvements to the quality of answers
for the default complex divide routine (half, float, double, extended,
long double precisions) when dealing with very large or very small exponents.
The current code correctly implements Smith's method (1962) [2]
further modified by c99's requirements for dealing with NaN (not a
number) results. When working with input values where the exponents
are greater than *_MAX_EXP/2 or less than -(*_MAX_EXP)/2, results are
substantially different from the answers provided by quad precision
more than 1% of the time. This error rate may be unacceptable for many
applications that cannot a priori restrict their computations to the
safe range. The proposed method reduces the frequency of
"substantially different" answers by more than 99% for double
precision at a modest cost of performance.
Differences between current gcc methods and the new method will be
described. Then accuracy and performance differences will be discussed.
Background
This project started with an investigation related to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59714. Study of Beebe[1]
provided an overview of past and recent practice for computing complex
divide. The current glibc implementation is based on Robert Smith's
algorithm [2] from 1962. A google search found the paper by Baudin
and Smith [3] (same Robert Smith) published in 2012. Elen Kalda's
proposed patch [4] is based on that paper.
I developed two sets of test data by randomly distributing values over
a restricted range and the full range of input values. The current
complex divide handled the restricted range well enough, but failed on
the full range more than 1% of the time. Baudin and Smith's primary
test for "ratio" equals zero reduced the cases with 16 or more error
bits by a factor of 5, but still left too many flawed answers. Adding
debug print out to cases with substantial errors allowed me to see the
intermediate calculations for test values that failed. I noted that
for many of the failures, "ratio" was a subnormal. Changing the
"ratio" test from check for zero to check for subnormal reduced the 16
bit error rate by another factor of 12. This single modified test
provides the greatest benefit for the least cost, but the percentage
of cases with greater than 16 bit errors (double precision data) is
still greater than 0.027% (2.7 in 10,000).
Continued examination of remaining errors and their intermediate
computations led to the various tests of input value tests and scaling
to avoid under/overflow. The current patch does not handle some of the
rare and most extreme combinations of input values, but the random
test data is only showing 1 case in 10 million that has an error of
greater than 12 bits. That case has 18 bits of error and is due to
subtraction cancellation. These results are significantly better
than the results reported by Baudin and Smith.
Support for half, float, double, extended, and long double precision
is included as all are handled with suitable preprocessor symbols in a
single source routine. Since half precision is computed with float
precision as per current libgcc practice, the enhanced algorithm
provides no benefit for half precision and would cost performance.
Further investigation showed changing the half precision algorithm
to use the simple formula (real=a*c+b*d imag=b*c-a*d) caused no
loss of precision and modest improvement in performance.
The existing constants for each precision:
float: FLT_MAX, FLT_MIN;
double: DBL_MAX, DBL_MIN;
extended and/or long double: LDBL_MAX, LDBL_MIN
are used for avoiding the more common overflow/underflow cases. This
use is made generic by defining appropriate __LIBGCC2_* macros in
c-cppbuiltin.c.
Tests are added for when both parts of the denominator have exponents
small enough to allow shifting any subnormal values to normal values
all input values could be scaled up without risking overflow. That
gained a clear improvement in accuracy. Similarly, when either
numerator was subnormal and the other numerator and both denominator
values were not too large, scaling could be used to reduce risk of
computing with subnormals. The test and scaling values used all fit
within the allowed exponent range for each precision required by the C
standard.
Float precision has more difficulty with getting correct answers than
double precision. When hardware for double precision floating point
operations is available, float precision is now handled in double
precision intermediate calculations with the simple algorithm the same
as the half-precision method of using float precision for intermediate
calculations. Using the higher precision yields exact results for all
tested input values (64-bit double, 32-bit float) with the only
performance cost being the requirement to convert the four input
values from float to double. If double precision hardware is not
available, then float complex divide will use the same improved
algorithm as the other precisions with similar change in performance.
Further Improvement
The most common remaining substantial errors are due to accuracy loss
when subtracting nearly equal values. This patch makes no attempt to
improve that situation.
NOTATION
For all of the following, the notation is:
Input complex values:
a+bi (a= real part, b= imaginary part)
c+di
Output complex value:
e+fi = (a+bi)/(c+di)
For the result tables:
current = current method (SMITH)
b1div = method proposed by Elen Kalda
b2div = alternate method considered by Elen Kalda
new = new method proposed by this patch
DESCRIPTIONS of different complex divide methods:
NAIVE COMPUTATION (-fcx-limited-range):
e = (a*c + b*d)/(c*c + d*d)
f = (b*c - a*d)/(c*c + d*d)
Note that c*c and d*d will overflow or underflow if either
c or d is outside the range 2^-538 to 2^512.
This method is available in gcc when the switch -fcx-limited-range is
used. That switch is also enabled by -ffast-math. Only one who has a
clear understanding of the maximum range of all intermediate values
generated by an application should consider using this switch.
SMITH's METHOD (current libgcc):
if(fabs(c)<fabs(d) {
r = c/d;
denom = (c*r) + d;
e = (a*r + b) / denom;
f = (b*r - a) / denom;
} else {
r = d/c;
denom = c + (d*r);
e = (a + b*r) / denom;
f = (b - a*r) / denom;
}
Smith's method is the current default method available with __divdc3.
Elen Kalda's METHOD
Elen Kalda proposed a patch about a year ago, also based on Baudin and
Smith, but not including tests for subnormals:
https://gcc.gnu.org/legacy-ml/gcc-patches/2019-08/msg01629.html [4]
It is compared here for accuracy with this patch.
This method applies the most significant part of the algorithm
proposed by Baudin&Smith (2012) in the paper "A Robust Complex
Division in Scilab" [3]. Elen's method also replaces two divides by
one divide and two multiplies due to the high cost of divide on
aarch64. In the comparison sections, this method will be labeled
b1div. A variation discussed in that patch which does not replace the
two divides will be labeled b2div.
inline void improved_internal (MTYPE a, MTYPE b, MTYPE c, MTYPE d)
{
r = d/c;
t = 1.0 / (c + (d * r));
if (r != 0) {
x = (a + (b * r)) * t;
y = (b - (a * r)) * t;
} else {
/* Changing the order of operations avoids the underflow of r impacting
the result. */
x = (a + (d * (b / c))) * t;
y = (b - (d * (a / c))) * t;
}
}
if (FABS (d) < FABS (c)) {
improved_internal (a, b, c, d);
} else {
improved_internal (b, a, d, c);
y = -y;
}
NEW METHOD (proposed by patch) to replace the current default method:
The proposed method starts with an algorithm proposed by Baudin&Smith
(2012) in the paper "A Robust Complex Division in Scilab" [3]. The
patch makes additional modifications to that method for further
reductions in the error rate. The following code shows the #define
values for double precision. See the patch for #define values used
for other precisions.
#define RBIG ((DBL_MAX)/2.0)
#define RMIN (DBL_MIN)
#define RMIN2 (0x1.0p-53)
#define RMINSCAL (0x1.0p+51)
#define RMAX2 ((RBIG)*(RMIN2))
if (FABS(c) < FABS(d)) {
/* prevent overflow when arguments are near max representable */
if ((FABS (d) > RBIG) || (FABS (a) > RBIG) || (FABS (b) > RBIG) ) {
a = a * 0.5;
b = b * 0.5;
c = c * 0.5;
d = d * 0.5;
}
/* minimize overflow/underflow issues when c and d are small */
else if (FABS (d) < RMIN2) {
a = a * RMINSCAL;
b = b * RMINSCAL;
c = c * RMINSCAL;
d = d * RMINSCAL;
}
else {
if(((FABS (a) < RMIN) && (FABS (b) < RMAX2) && (FABS (d) < RMAX2)) ||
((FABS (b) < RMIN) && (FABS (a) < RMAX2) && (FABS (d) < RMAX2))) {
a = a * RMINSCAL;
b = b * RMINSCAL;
c = c * RMINSCAL;
d = d * RMINSCAL;
}
}
r = c/d; denom = (c*r) + d;
if( r > RMIN ) {
e = (a*r + b) / denom ;
f = (b*r - a) / denom
} else {
e = (c * (a/d) + b) / denom;
f = (c * (b/d) - a) / denom;
}
}
[ only presenting the fabs(c) < fabs(d) case here, full code in patch. ]
Before any computation of the answer, the code checks for any input
values near maximum to allow down scaling to avoid overflow. These
scalings almost never harm the accuracy since they are by 2. Values that
are over RBIG are relatively rare but it is easy to test for them and
allow aviodance of overflows.
Testing for RMIN2 reveals when both c and d are less than [FLT|DBL]_EPSILON.
By scaling all values by 1/EPSILON, the code converts subnormals to normals,
avoids loss of accuracy and underflows in intermediate computations
that otherwise might occur. If scaling a and b by 1/EPSILON causes either
to overflow, then the computation will overflow whatever method is used.
Finally, we test for either a or b being subnormal (RMIN) and if so,
for the other three values being small enough to allow scaling. We
only need to test a single denominator value since we have already
determined which of c and d is larger.
Next, r (the ratio of c to d) is checked for being near zero. Baudin
and Smith checked r for zero. This code improves that approach by
checking for values less than DBL_MIN (subnormal) covers roughly 12
times as many cases and substantially improves overall accuracy. If r
is too small, then when it is used in a multiplication, there is a
high chance that the result will underflow to zero, losing significant
accuracy. That underflow is avoided by reordering the computation.
When r is subnormal, the code replaces a*r (= a*(c/d)) with ((a/d)*c)
which is mathematically the same but avoids the unnecessary underflow.
TEST Data
Two sets of data are presented to test these methods. Both sets
contain 10 million pairs of complex values. The exponents and
mantissas are generated using multiple calls to random() and then
combining the results. Only values which give results to complex
divide that are representable in the appropriate precision after
being computed in quad precision are used.
The first data set is labeled "moderate exponents".
The exponent range is limited to -DBL_MAX_EXP/2 to DBL_MAX_EXP/2
for Double Precision (use FLT_MAX_EXP or LDBL_MAX_EXP for the
appropriate precisions.
The second data set is labeled "full exponents".
The exponent range for these cases is the full exponent range
including subnormals for a given precision.
ACCURACY Test results:
Note: The following accuracy tests are based on IEEE-754 arithmetic.
Note: All results reporteed are based on use of fused multiply-add. If
fused multiply-add is not used, the error rate increases, giving more
1 and 2 bit errors for both current and new complex divide.
Differences between using fused multiply and not using it that are
greater than 2 bits are less than 1 in a million.
The complex divide methods are evaluated by determining the percentage
of values that exceed differences in low order bits. If a "2 bit"
test results show 1%, that would mean that 1% of 10,000,000 values
(100,000) have either a real or imaginary part that differs from the
quad precision result by more than the last 2 bits.
Results are reported for differences greater than or equal to 1 bit, 2
bits, 8 bits, 16 bits, 24 bits, and 52 bits for double precision. Even
when the patch avoids overflows and underflows, some input values are
expected to have errors due to the potential for catastrophic roundoff
from floating point subtraction. For example, when b*c and a*d are
nearly equal, the result of subtraction may lose several places of
accuracy. This patch does not attempt to detect or minimize this type
of error, but neither does it increase them.
I only show the results for Elen Kalda's method (with both 1 and
2 divides) and the new method for only 1 divide in the double
precision table.
In the following charts, lower values are better.
current - current complex divide in libgcc
b1div - Elen Kalda's method from Baudin & Smith with one divide
b2div - Elen Kalda's method from Baudin & Smith with two divides
new - This patch which uses 2 divides
===================================================
Errors Moderate Dataset
gtr eq current b1div b2div new
====== ======== ======== ======== ========
1 bit 0.24707% 0.92986% 0.24707% 0.24707%
2 bits 0.01762% 0.01770% 0.01762% 0.01762%
8 bits 0.00026% 0.00026% 0.00026% 0.00026%
16 bits 0.00000% 0.00000% 0.00000% 0.00000%
24 bits 0% 0% 0% 0%
52 bits 0% 0% 0% 0%
===================================================
Table 1: Errors with Moderate Dataset (Double Precision)
Note in Table 1 that both the old and new methods give identical error
rates for data with moderate exponents. Errors exceeding 16 bits are
exceedingly rare. There are substantial increases in the 1 bit error
rates for b1div (the 1 divide/2 multiplys method) as compared to b2div
(the 2 divides method). These differences are minimal for 2 bits and
larger error measurements.
===================================================
Errors Full Dataset
gtr eq current b1div b2div new
====== ======== ======== ======== ========
1 bit 2.05% 1.23842% 0.67130% 0.16664%
2 bits 1.88% 0.51615% 0.50354% 0.00900%
8 bits 1.77% 0.42856% 0.42168% 0.00011%
16 bits 1.63% 0.33840% 0.32879% 0.00001%
24 bits 1.51% 0.25583% 0.24405% 0.00000%
52 bits 1.13% 0.01886% 0.00350% 0.00000%
===================================================
Table 2: Errors with Full Dataset (Double Precision)
Table 2 shows significant differences in error rates. First, the
difference between b1div and b2div show a significantly higher error
rate for the b1div method both for single bit errros and well
beyond. Even for 52 bits, we see the b1div method gets completely
wrong answers more than 5 times as often as b2div. To retain
comparable accuracy with current complex divide results for small
exponents and due to the increase in errors for large exponents, I
choose to use the more accurate method of two divides.
The current method has more 1.6% of cases where it is getting results
where the low 24 bits of the mantissa differ from the correct
answer. More than 1.1% of cases where the answer is completely wrong.
The new method shows less than one case in 10,000 with greater than
two bits of error and only one case in 10 million with greater than
16 bits of errors. The new patch reduces 8 bit errors by
a factor of 16,000 and virtually eliminates completely wrong
answers.
As noted above, for architectures with double precision
hardware, the new method uses that hardware for the
intermediate calculations before returning the
result in float precision. Testing of the new patch
has shown zero errors found as seen in Tables 3 and 4.
Correctness for float
=============================
Errors Moderate Dataset
gtr eq current new
====== ======== ========
1 bit 28.68070% 0%
2 bits 0.64386% 0%
8 bits 0.00401% 0%
16 bits 0.00001% 0%
24 bits 0% 0%
=============================
Table 3: Errors with Moderate Dataset (float)
=============================
Errors Full Dataset
gtr eq current new
====== ======== ========
1 bit 19.98% 0%
2 bits 3.20% 0%
8 bits 1.97% 0%
16 bits 1.08% 0%
24 bits 0.55% 0%
=============================
Table 4: Errors with Full Dataset (float)
As before, the current method shows an troubling rate of extreme
errors.
There very minor changes in accuracy for half-precision since the code
changes from Smith's method to the simple method. 5 out of 1 million
test cases show correct answers instead of 1 or 2 bit errors.
libgcc computes half-precision functions in float precision
allowing the existing methods to avoid overflow/underflow issues
for the allowed range of exponents for half-precision.
Extended precision (using x87 80-bit format on x86) and Long double
(using IEEE-754 128-bit on x86 and aarch64) both have 15-bit exponents
as compared to 11-bit exponents in double precision. We note that the
C standard also allows Long Double to be implemented in the equivalent
range of Double. The RMIN2 and RMINSCAL constants are selected to work
within the Double range as well as with extended and 128-bit ranges.
We will limit our performance and accurancy discussions to the 80-bit
and 128-bit formats as seen on x86 here.
The extended and long double precision investigations were more
limited. Aarch64 does not support extended precision but does support
the software implementation of 128-bit long double precision. For x86,
long double defaults to the 80-bit precision but using the
-mlong-double-128 flag switches to using the software implementation
of 128-bit precision. Both 80-bit and 128-bit precisions have the same
exponent range, with the 128-bit precision has extended mantissas.
Since this change is only aimed at avoiding underflow/overflow for
extreme exponents, I studied the extended precision results on x86 for
100,000 values. The limited exponent dataset showed no differences.
For the dataset with full exponent range, the current and new values
showed major differences (greater than 32 bits) in 567 cases out of
100,000 (0.56%). In every one of these cases, the ratio of c/d or d/c
(as appropriate) was zero or subnormal, indicating the advantage of
the new method and its continued correctness where needed.
PERFORMANCE Test results
In order for a library change to be practical, it is necessary to show
the slowdown is tolerable. The slowdowns observed are much less than
would be seen by (for example) switching from hardware double precison
to a software quad precision, which on the tested machines causes a
slowdown of around 100x).
The actual slowdown depends on the machine architecture. It also
depends on the nature of the input data. If underflow/overflow is
rare, then implementations that have strong branch prediction will
only slowdown by a few cycles. If underflow/overflow is common, then
the branch predictors will be less accurate and the cost will be
higher.
Results from two machines are presented as examples of the overhead
for the new method. The one labeled x86 is a 5 year old Intel x86
processor and the one labeled aarch64 is a 3 year old arm64 processor.
In the following chart, the times are averaged over a one million
value data set. All values are scaled to set the time of the current
method to be 1.0. Lower values are better. A value of less than 1.0
would be faster than the current method and a value greater than 1.0
would be slower than the current method.
================================================
Moderate set full set
x86 aarch64 x86 aarch64
======== =============== ===============
float 0.59 0.79 0.45 0.81
double 1.04 1.24 1.38 1.56
long double 1.13 1.24 1.29 1.25
================================================
Table 5: Performance Comparisons (ratio new/current)
The above tables omit the timing for the 1 divide and 2 multiply
comparison with the 2 divide approach.
The float results show clear performance improvement due to using the
simple method with double precision for intermediate calculations.
The double results with the newer method show less overhead for the
moderate dataset than for the full dataset. That's because the moderate
dataset does not ever take the new branches which protect from
under/overflow. The better the branch predictor, the lower the cost
for these untaken branches. Both platforms are somewhat dated, with
the x86 having a better branch predictor which reduces the cost of the
additional branches in the new code. Of course, the relative slowdown
may be greater for some architectures, especially those with limited
branch prediction combined with a high cost of misprediction.
The long double results are fairly consistent in showing the moderate
additional cost of the extra branches and calculations for all cases.
The observed cost for all precisions is claimed to be tolerable on the
grounds that:
(a) the cost is worthwhile considering the accuracy improvement shown.
(b) most applications will only spend a small fraction of their time
calculating complex divide.
(c) it is much less than the cost of extended precision
(d) users are not forced to use it (as described below)
Those users who find this degree of slowdown unsatisfactory may use
the gcc switch -fcx-fortran-rules which does not use the library
routine, instead inlining Smith's method without the C99 requirement
for dealing with NaN results. The proposed patch for libgcc complex
divide does not affect the code generated by -fcx-fortran-rules.
SUMMARY
When input data to complex divide has exponents whose absolute value
is less than half of *_MAX_EXP, this patch makes no changes in
accuracy and has only a modest effect on performance. When input data
contains values outside those ranges, the patch eliminates more than
99.9% of major errors with a tolerable cost in performance.
In comparison to Elen Kalda's method, this patch introduces more
performance overhead but reduces major errors by a factor of
greater than 4000.
REFERENCES
[1] Nelson H.F. Beebe, "The Mathematical-Function Computation Handbook.
Springer International Publishing AG, 2017.
[2] Robert L. Smith. Algorithm 116: Complex division. Commun. ACM,
5(8):435, 1962.
[3] Michael Baudin and Robert L. Smith. "A robust complex division in
Scilab," October 2012, available at http://arxiv.org/abs/1210.4539.
[4] Elen Kalda: Complex division improvements in libgcc
https://gcc.gnu.org/legacy-ml/gcc-patches/2019-08/msg01629.html
2020-12-08 Patrick McGehearty <patrick.mcgehearty@oracle.com>
gcc/c-family/
* c-cppbuiltin.c (c_cpp_builtins): Add supporting macros for new
complex divide
libgcc/
* libgcc2.c (XMTYPE, XCTYPE, RBIG, RMIN, RMIN2, RMINSCAL, RMAX2):
Define.
(__divsc3, __divdc3, __divxc3, __divtc3): Improve complex divide.
* config/rs6000/_divkc3.c (RBIG, RMIN, RMIN2, RMINSCAL, RMAX2):
Define.
(__divkc3): Improve complex divide.
gcc/testsuite/
* gcc.c-torture/execute/ieee/cdivchkd.c: New test.
* gcc.c-torture/execute/ieee/cdivchkf.c: Likewise.
* gcc.c-torture/execute/ieee/cdivchkld.c: Likewise.
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... to diagnose potentially suboptimal choices regarding OpenACC parallelism.
Not enabled by default: too noisy ("*potentially* suboptimal choices"); see
XFAILed 'dg-bogus'es.
gcc/c-family/
* c.opt (Wopenacc-parallelism): New.
gcc/fortran/
* lang.opt (Wopenacc-parallelism): New.
gcc/
* omp-offload.c (oacc_validate_dims): Implement
'-Wopenacc-parallelism'.
* doc/invoke.texi (-Wopenacc-parallelism): Document.
gcc/testsuite/
* c-c++-common/goacc/diag-parallelism-1.c: New.
* c-c++-common/goacc/acc-icf.c: Specify '-Wopenacc-parallelism',
and match diagnostics, as appropriate.
* c-c++-common/goacc/classify-kernels-unparallelized.c: Likewise.
* c-c++-common/goacc/classify-kernels.c: Likewise.
* c-c++-common/goacc/classify-parallel.c: Likewise.
* c-c++-common/goacc/classify-routine.c: Likewise.
* c-c++-common/goacc/classify-serial.c: Likewise.
* c-c++-common/goacc/kernels-decompose-1.c: Likewise.
* c-c++-common/goacc/kernels-decompose-2.c: Likewise.
* c-c++-common/goacc/parallel-dims-1.c: Likewise.
* c-c++-common/goacc/parallel-reduction.c: Likewise.
* c-c++-common/goacc/pr70688.c: Likewise.
* c-c++-common/goacc/routine-1.c: Likewise.
* c-c++-common/goacc/routine-level-of-parallelism-2.c: Likewise.
* c-c++-common/goacc/uninit-dim-clause.c: Likewise.
* gfortran.dg/goacc/classify-kernels-unparallelized.f95: Likewise.
* gfortran.dg/goacc/classify-kernels.f95: Likewise.
* gfortran.dg/goacc/classify-parallel.f95: Likewise.
* gfortran.dg/goacc/classify-routine.f95: Likewise.
* gfortran.dg/goacc/classify-serial.f95: Likewise.
* gfortran.dg/goacc/kernels-decompose-1.f95: Likewise.
* gfortran.dg/goacc/kernels-decompose-2.f95: Likewise.
* gfortran.dg/goacc/parallel-tree.f95: Likewise.
* gfortran.dg/goacc/routine-4.f90: Likewise.
* gfortran.dg/goacc/routine-level-of-parallelism-1.f90: Likewise.
* gfortran.dg/goacc/routine-module-mod-1.f90: Likewise.
* gfortran.dg/goacc/routine-multiple-directives-1.f90: Likewise.
* gfortran.dg/goacc/uninit-dim-clause.f95: Likewise.
libgomp/
* testsuite/libgomp.oacc-c-c++-common/firstprivate-1.c: Specify
'-Wopenacc-parallelism', and match diagnostics, as appropriate.
* testsuite/libgomp.oacc-c-c++-common/loop-auto-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/loop-red-w-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/loop-red-w-2.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/loop-w-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/mode-transitions.c:
Likewise.
* testsuite/libgomp.oacc-c-c++-common/par-reduction-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/par-reduction-2.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/parallel-dims.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/parallel-reduction.c:
Likewise.
* testsuite/libgomp.oacc-c-c++-common/pr85381-3.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/private-variables.c:
Likewise.
* testsuite/libgomp.oacc-c-c++-common/reduction-5.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/reduction-7.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/routine-g-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/routine-w-1.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/routine-wv-2.c: Likewise.
* testsuite/libgomp.oacc-c-c++-common/static-variable-1.c:
Likewise.
* testsuite/libgomp.oacc-fortran/optional-private.f90: Likewise.
* testsuite/libgomp.oacc-fortran/par-reduction-2-1.f: Likewise.
* testsuite/libgomp.oacc-fortran/par-reduction-2-2.f: Likewise.
* testsuite/libgomp.oacc-fortran/parallel-dims.f90: Likewise.
* testsuite/libgomp.oacc-fortran/parallel-reduction.f90: Likewise.
* testsuite/libgomp.oacc-fortran/pr84028.f90: Likewise.
* testsuite/libgomp.oacc-fortran/private-variables.f90: Likewise.
* testsuite/libgomp.oacc-fortran/reduction-1.f90: Likewise.
* testsuite/libgomp.oacc-fortran/reduction-5.f90: Likewise.
* testsuite/libgomp.oacc-fortran/reduction-6.f90: Likewise.
* testsuite/libgomp.oacc-fortran/routine-7.f90: Likewise.
Co-Authored-By: Nathan Sidwell <nathan@codesourcery.com>
Co-Authored-By: Tom de Vries <vries@codesourcery.com>
Co-Authored-By: Julian Brown <julian@codesourcery.com>
Co-Authored-By: Kwok Cheung Yeung <kcy@codesourcery.com>
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This configuration knob is temporary, and isn't really meant to be exposed to
users.
gcc/
* params.opt (-param=openacc-kernels=): Add.
* omp-oacc-kernels-decompose.cc
(pass_omp_oacc_kernels_decompose::gate): Use it.
* doc/invoke.texi (-fopenacc-kernels=@var{mode}): Move...
(--param): ... here, 'openacc-kernels'.
gcc/c-family/
* c.opt (fopenacc-kernels=): Remove.
gcc/fortran/
* lang.opt (fopenacc-kernels=): Remove.
gcc/testsuite/
* c-c++-common/goacc/if-clause-2.c: '-fopenacc-kernels=[...]' ->
'--param=openacc-kernels=[...]'.
* c-c++-common/goacc/kernels-decompose-1.c: Likewise.
* c-c++-common/goacc/kernels-decompose-2.c: Likewise.
* c-c++-common/goacc/kernels-decompose-ice-1.c: Likewise.
* c-c++-common/goacc/kernels-decompose-ice-2.c: Likewise.
* gfortran.dg/goacc/kernels-decompose-1.f95: Likewise.
* gfortran.dg/goacc/kernels-decompose-2.f95: Likewise.
* gfortran.dg/goacc/kernels-tree.f95: Likewise.
libgomp/
* testsuite/libgomp.oacc-c-c++-common/declare-vla-kernels-decompose-ice-1.c:
'-fopenacc-kernels=[...]' -> '--param=openacc-kernels=[...]'.
* testsuite/libgomp.oacc-c-c++-common/declare-vla-kernels-decompose.c:
Likewise.
* testsuite/libgomp.oacc-c-c++-common/kernels-decompose-1.c:
Likewise.
* testsuite/libgomp.oacc-fortran/pr94358-1.f90: Likewise.
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When looking into PR99420, I have noticed several comment typos.
2021-04-08 Jakub Jelinek <jakub@redhat.com>
* c-warn.c (do_warn_double_promotion): Fix comment typo,
occured -> occurred.
(check_alignment_of_packed_member): Fix a comment typo,
memeber -> member.
(warn_parm_ptrarray_mismatch): Fix comment typos, os -> of
and onless -> unless.
(warn_parm_array_mismatch): Fix comment typos, declaratation
-> declaration and woud -> would. Fix up comment indentation.
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gcc/c-family/ChangeLog:
PR middle-end/99883
* c.opt (Wmismatched-new-delete): Correct spelling.
gcc/lto/ChangeLog:
PR middle-end/99883
* lto-lang.c (lto_post_options): Correct spelling.
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When the enumeration constants of an enumeration type are defined by
explicit values, the binding generated by -fdump-ada-spec does not use
an enumeration type on the Ada side, because the set of allowed values
in C/C++ is larger than the set of allowed values in Ada, but instead
use an integer subtype and defines a set of explicit constants, which
used to be of this subtype but were changed to the base type at some
point. This reinstates the subtype for them.
gcc/c-family/
* c-ada-spec.c (is_simple_enum): Minor tweaks.
(dump_ada_enum_type): Add TYPE and PARENT parameters. For non-simple
enumeral types use again the type name for the enumeration constants.
(dump_ada_node): Adjust call to dump_ada_enum_type.
(dump_nested_type): Likewise.
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The PR98481 fix corrects an ABI regression in GCC 10, but we don't want to
introduce an ABI change in the middle of the GCC 10 cycle. This patch
introduces ABI v15 for the fix, which will be available but not default in
GCC 10.3; the broken behavior remains in ABI v14. Compatibility aliases
will not be generated for this change.
gcc/ChangeLog:
PR c++/98481
* common.opt: Document v15 and v16.
gcc/c-family/ChangeLog:
PR c++/98481
* c-opts.c (c_common_post_options): Bump latest_abi_version.
gcc/cp/ChangeLog:
PR c++/98481
* mangle.c (write_expression): Adjust.
* class.c (find_abi_tags_r): Disable PR98481 fix for ABI v14.
(mark_abi_tags_r): Likewise.
gcc/testsuite/ChangeLog:
PR c++/98481
* g++.dg/abi/abi-tag24a.C: New test.
* g++.dg/abi/macro0.C: Adjust expected value.
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Honza has fairly recently changed operand_equal_p to compare
DECL_FIELD_OFFSET for COMPONENT_REFs when comparing addresses.
As the first testcase in this patch shows, while that is very nice
for optimizations, for the -Wduplicated-branches warning it causes
regressions. Pedantically a union in both C and C++ has only one
active member at a time, so using some other union member even if it has the
same type is UB, so I think the warning shouldn't warn when it sees access
to different fields that happen to have the same offset and should consider
them different.
In my first attempt to fix this I've keyed the old behavior on
OEP_LEXICOGRAPHIC, but unfortunately that has various problems, the warning
has a quick non-lexicographic compare in build_conditional_expr* and another
lexicographic more expensive one later during genericization and turning the
first one into lexicographic would mean wasting compile time on large
conditionals.
So, this patch instead introduces a new OEP_ flag and makes sure to pass it
to operand_equal_p in all -Wduplicated-branches cases.
The cvt.c changes are because on the other testcase we were warning with
UNKNOWN_LOCATION, so the user wouldn't really know where the questionable
code is.
2021-03-25 Jakub Jelinek <jakub@redhat.com>
PR c++/99565
* tree-core.h (enum operand_equal_flag): Add OEP_ADDRESS_OF_SAME_FIELD.
* fold-const.c (operand_compare::operand_equal_p): Don't compare
field offsets if OEP_ADDRESS_OF_SAME_FIELD.
* c-warn.c (do_warn_duplicated_branches): Pass also
OEP_ADDRESS_OF_SAME_FIELD to operand_equal_p.
* c-typeck.c (build_conditional_expr): Pass OEP_ADDRESS_OF_SAME_FIELD
to operand_equal_p.
* call.c (build_conditional_expr_1): Pass OEP_ADDRESS_OF_SAME_FIELD
to operand_equal_p.
* cvt.c (convert_to_void): Preserve location_t on COND_EXPR or
or COMPOUND_EXPR.
* g++.dg/warn/Wduplicated-branches6.C: New test.
* g++.dg/warn/Wduplicated-branches7.C: New test.
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The following testcase results in -fcompare-debug failure.
The problem is the similar like in PR94272
https://gcc.gnu.org/pipermail/gcc-patches/2020-March/542562.html
When genericizing, with -g0 we have just a TREE_SIDE_EFFECTS DO_STMT
in a branch of if, while with -g we have that wrapped into
TREE_SIDE_EFFECTS STATEMENT_LIST containing DEBUG_BEGIN_STMT and that
DO_STMT.
The do loop is empty with 0 condition, so c_genericize_control_stmt
turns it into an empty statement (without TREE_SIDE_EFFECTS).
For -g0 that means that suddenly the if branch doesn't have side effects
and is expanded differently. But with -g we still have TREE_SIDE_EFFECTS
STATEMENT_LIST containing DEBUG_BEGIN_STMT and non-TREE_SIDE_EFFECTS stmt.
The following patch fixes that by detecting this case and removing
TREE_SIDE_EFFECTS.
And, so that we don't duplicate the same code, changes the C++ FE to
just call the c_genericize_control_stmt function that can now handle it.
2021-03-20 Jakub Jelinek <jakub@redhat.com>
PR debug/99230
* c-gimplify.c (c_genericize_control_stmt): Handle STATEMENT_LIST.
* cp-gimplify.c (cp_genericize_r) <case STATEMENT_LIST>: Remove
special code, instead call c_genericize_control_stmt.
* gcc.dg/pr99230.c: New test.
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gcc/c-family/
* c-ada-spec.c (dump_ada_declaration) <TYPE_DECL>: Dump nested types
after entering the separate class package, if any.
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The gcc.dg/noncompile/pr79758.c testcase prints
pr79758.c:5:6: error: redefinition of 'fn1'
'error_mark' not supported by direct_abstract_declarator)'/home/rguenther/src/gcc3/gcc/testsuite/gcc.dg/noncompile/pr79758.c:4:6: note: previous definition of 'fn1' with type
which shows a) re-entry of pp_printf via pp_unsupported_tree and b) a
bogus diagnostic. The following handles ERROR_MARK in
direct_abstract_declarator, yielding in the better
/home/rguenther/src/gcc3/gcc/testsuite/gcc.dg/noncompile/pr79758.c:5:6: error: redefinition of 'fn1'
/home/rguenther/src/gcc3/gcc/testsuite/gcc.dg/noncompile/pr79758.c:4:6: note: previous definition of 'fn1' with type 'void(<type-error>)'
but still maybe not perfect.
2021-03-04 Richard Biener <rguenther@suse.de>
gcc/c-family/
* c-pretty-print.c (c_pretty_printer::direct_abstract_declarator):
Handle ERROR_MARK.
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In libcpp, lines are represented as linenum_type, which is unsigned int.
The following testcases ICE because maybe_print_line_1 is sometimes called
with UNKNOWN_LOCATION (e.g. at pragma eof) and while most of the time
the
&& src_line >= print.src_line
&& src_line < print.src_line + 8
check doesn't succeed for the src_line of 0 from UNKNOWN_LOCATION, when
print.src_line is from very large line numbers (UINT_MAX - 7 and above)
it succeeds (with UB on the compiler side) but src_file is NULL for
UNKNOWN_LOCATION and so the strcmp call ICEs.
As print.src_line can easily wrap around, this patch changes its type
to unsigned int to match libcpp, so that we don't invoke UB in the compiler.
For print.src_line of UINT_MAX - 7 and above, src_line from UNKNOWN_LOCATION
will not pass that test anymore, but when it wraps around to 0, it can,
so I've also added a check for src_loc != UNKNOWN_LOCATION (or, if
preferred, could be src_file != NULL).
Besides fixing the ICE and UB in the compiler, I believe worst case the
patch will cause printing a few more line directives in the preprocessed
source around the wrapping from lines UINT_MAX - 7 to 0 (but less
around the wrapping from INT_MAX to INT_MAX + 1U), but I think those
are exceptional cases (sources with > 2billion lines are rare and
we warn or error on #line > INT_MAX).
2021-03-04 Jakub Jelinek <jakub@redhat.com>
PR c/99325
* c-ppoutput.c (print): Change src_line type from int to unsigned.
(token_streamer::stream) Likewise.
(maybe_print_line_1): Likewise. Don't strcmp src_file if src_loc is
UNKNOWN_LOCATION.
* gcc.dg/cpp/line11.c: New test.
* gcc.dg/cpp/line12.c: New test.
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build_va_arg calls the middle-end mark_addressable, which e.g. requires that
cfun is non-NULL. The following patch calls instead c_common_mark_addressable_vec
which is the c-family variant similarly to the FE c_mark_addressable and
cxx_mark_addressable, except that it doesn't error on addresses of register
variables. As the taking of the address is artificial for the .VA_ARG
ifn and when that is lowered goes away, it is similar case to the vector
subscripting for which c_common_mark_addressable_vec has been added.
2021-03-03 Jakub Jelinek <jakub@redhat.com>
PR c/99324
* c-common.c (build_va_arg): Call c_common_mark_addressable_vec
instead of mark_addressable. Fix a comment typo -
neutrallly -> neutrally.
* gcc.c-torture/compile/pr99324.c: New test.
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The PR is about a typo in handle_malloc_attribute diagnostic message,
but grepping around I found many other cases and while fixing those I've
noticed a couple of other typos.
2021-02-28 Jakub Jelinek <jakub@redhat.com>
PR c/99304
* ipa.c (symbol_table::remove_unreachable_nodes): Fix a comment
typo - referneced -> referenced.
* tree.c (component_ref_size): Fix comment typo -
refernce -> reference.
* tree-ssa-alias.c (access_path_may_continue_p): Fix comment typo -
traling -> trailing.
(aliasing_component_refs_p): Fix comment typos -
refernce -> reference and refernece -> reference and
traling -> trailing.
(nonoverlapping_refs_since_match_p): Fix comment typo -
referneces -> references.
* doc/invoke.texi (--param modref-max-bases): Fix a typo -
referneces -> references.
gcc/c-family/
* c-attribs.c (handle_malloc_attribute): Fix a typo in inform
message - refernced -> referenced. Remove superfluous space before
closing paren of function calls.
gcc/lto/
* lto-symtab.c (lto_symtab_prevailing_virtual_decl): Fix comment
typos - refernced -> referenced and
devirtualizaiton -> devirtualization.
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I realized that the just-added flang-note-module-read option should
also cover module writes, and was therefore misnamed. This addresses
that, replacing it with a -flang-note-module-cmi pair of options. As
this was such a recent addition, I didn't leave the old option
available.
PR c++/99166
gcc/c-family/
* c.opt (-flang-info-module-cmi): Renamed option.
gcc/
* doc/invoke.texi (flang-info-module-cmi): Renamed option.
gcc/cp/
* module.cc (module_state::inform_cmi_p): Renamed field.
(module_state::do_import): Adjust.
(init_modules, finish_module_processing): Likewise.
(handle_module_option): Likewise.
gcc/testsuite/
* g++.dg/modules/pr99166_a.X: Adjust.
* g++.dg/modules/pr99166_b.C: Adjust.
* g++.dg/modules/pr99166_c.C: Adjust.
* g++.dg/modules/pr99166_d.C: Adjust.
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When successfully reading a module CMI, the user gets no indication of
where that CMI was located. I originally didn't consider this a
problem -- the read was successful after all. But it can make it
difficult to interact with build systems, particularly when caching
can be involved. Grovelling over internal dump files is not really
useful to the user. Hence this option, which is similar to the
-flang-info-include-translate variants, and allows the user to ask for
all, or specific module read notification.
gcc/c-family/
* c.opt (flang-info-module-read, flang-info-module-read=): New.
gcc/
* doc/invoke.texi (flang-info-module-read): Document.
gcc/cp/
* module.cc (note_cmis): New.
(struct module_state): Add inform_read_p bit.
(module_state::do_import): Inform of CMI location, if enabled.
(init_modules): Canonicalize note_cmis entries.
(handle_module_option): Handle -flang-info-module-read=FOO.
gcc/testsuite/
* g++.dg/modules/pr99166_a.X: New.
* g++.dg/modules/pr99166_b.C: New.
* g++.dg/modules/pr99166_c.C: New.
* g++.dg/modules/pr99166_d.C: New.
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When building Linux kernel, ld in bninutils 2.36 with GCC 11 generates
thousands of
ld: warning: orphan section `.data.event_initcall_finish' from `init/main.o' being placed in section `.data.event_initcall_finish'
ld: warning: orphan section `.data.event_initcall_start' from `init/main.o' being placed in section `.data.event_initcall_start'
ld: warning: orphan section `.data.event_initcall_level' from `init/main.o' being placed in section `.data.event_initcall_level'
Since these sections are marked with SHF_GNU_RETAIN, they are placed in
separate sections. They become orphan sections since they aren't expected
in the Linux kernel linker script. But orphan sections normally don't work
well with the Linux kernel linker script and the resulting kernel crashed.
Add the "retain" attribute to place symbols in separate SHF_GNU_RETAIN
sections. Issue a warning if the configured assembler/linker doesn't
support SHF_GNU_RETAIN.
gcc/
PR target/99113
* varasm.c (get_section): Replace SUPPORTS_SHF_GNU_RETAIN with
looking up the retain attribute.
(resolve_unique_section): Likewise.
(get_variable_section): Likewise.
(switch_to_section): Likewise. Warn when a symbol without the
retain attribute and a symbol with the retain attribute are
placed in the section with the same name, instead of the used
attribute.
* doc/extend.texi: Document the "retain" attribute.
gcc/c-family/
PR target/99113
* c-attribs.c (c_common_attribute_table): Add the "retain"
attribute.
(handle_retain_attribute): New function.
gcc/testsuite/
PR target/99113
* c-c++-common/attr-retain-1.c: New test.
* c-c++-common/attr-retain-2.c: Likewise.
* c-c++-common/attr-retain-3.c: Likewise.
* c-c++-common/attr-retain-4.c: Likewise.
* c-c++-common/attr-retain-5.c: Likewise.
* c-c++-common/attr-retain-6.c: Likewise.
* c-c++-common/attr-retain-7.c: Likewise.
* c-c++-common/attr-retain-8.c: Likewise.
* c-c++-common/attr-retain-9.c: Likewise.
* c-c++-common/pr99113.c: Likewise.
* gcc.c-torture/compile/attr-retain-1.c: Likewise.
* gcc.c-torture/compile/attr-retain-2.c: Likewise.
* c-c++-common/attr-used.c: Don't expect SHF_GNU_RETAIN section.
* c-c++-common/attr-used-2.c: Likewise.
* c-c++-common/attr-used-3.c: Likewise.
* c-c++-common/attr-used-4.c: Likewise.
* c-c++-common/attr-used-9.c: Likewise.
* gcc.c-torture/compile/attr-used-retain-1.c: Likewise.
* gcc.c-torture/compile/attr-used-retain-2.c: Likewise.
* c-c++-common/attr-used-5.c: Don't expect warning for the used
attribute nor SHF_GNU_RETAIN section.
* c-c++-common/attr-used-6.c: Likewise.
* c-c++-common/attr-used-7.c: Likewise.
* c-c++-common/attr-used-8.c: Likewise.
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We ICE in handle_assume_aligned_attribute since r271338 which added
@@ -2935,8 +2936,8 @@ handle_assume_aligned_attribute (tree *node, tree name, tree args, int,
/* The misalignment specified by the second argument
must be non-negative and less than the alignment. */
warning (OPT_Wattributes,
- "%qE attribute argument %E is not in the range [0, %E)",
- name, val, align);
+ "%qE attribute argument %E is not in the range [0, %wu]",
+ name, val, tree_to_uhwi (align) - 1);
*no_add_attrs = true;
return NULL_TREE;
}
because align is INT_MIN and tree_to_uhwi asserts tree_fits_uhwi_p -- which
ALIGN does not and the prior tree_fits_shwi_p check is fine with it, as
well as the integer_pow2p check.
Since neither of the arguments to assume_aligned can be negative, I've
hoisted the tree_int_cst_sgn check. And add the missing "argument"
word to an existing warning.
gcc/c-family/ChangeLog:
PR c++/99062
* c-attribs.c (handle_assume_aligned_attribute): Check that the
alignment argument is non-negative. Tweak a warning message.
gcc/testsuite/ChangeLog:
PR c++/99062
* gcc.dg/attr-assume_aligned-4.c: Adjust dg-warning.
* g++.dg/ext/attr-assume-aligned.C: New test.
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gcc/c-family/ChangeLog:
PR c/99055
* c-warn.c (warn_parm_array_mismatch): Free strings returned from
print_generic_expr_to_str.
gcc/ChangeLog:
* tree-pretty-print.c (print_generic_expr_to_str): Update comment.
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The optimize pragma/attribute parsing calls decode_cmdline_options_to_array
but doesn't free the array. The following fixes that.
2021-02-10 Richard Biener <rguenther@suse.de>
gcc/c-family/
* c-common.c (parse_optimize_options): Free decoded_options.
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The value of __cpp_size_t_suffix is 202011 not 202006.
gcc/c-family/ChangeLog:
* c-cppbuiltin.c (c_cpp_builtins): __cpp_size_t_suffix=202011L.
gcc/testsuite/ChangeLog:
* g++.dg/cpp23/feat-cxx2b.C: __cpp_size_t_suffix == 202011.
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Integer literal suffixes for signed size ('z') and unsigned size
(some permutation od 'zu') are provided as a language addition.
gcc/c-family/ChangeLog:
* c-cppbuiltin.c (c_cpp_builtins): Define __cpp_size_t_suffix.
* c-lex.c (interpret_integer): Set node type for size literal.
libcpp/ChangeLog:
* expr.c (interpret_int_suffix): Detect 'z' integer suffix.
(cpp_classify_number): Compat warning for use of 'z' suffix.
* include/cpplib.h (struct cpp_options): New flag.
(enum cpp_warning_reason): New flag.
(CPP_N_USERDEF): Comment C++0x -> C++11.
(CPP_N_SIZE_T): New flag for cpp_classify_number.
* init.c (cpp_set_lang): Initialize new flag.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/udlit-shadow-neg.C: Test for 'z' and 'zu' shadowing.
* g++.dg/cpp23/feat-cxx2b.C: New test.
* g++.dg/cpp23/size_t-literals.C: New test.
* g++.dg/warn/Wsize_t-literals.C: New test.
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I've noticed we still refer to C++20 as draft standard, and there is a pasto
in C++23 description.
2021-01-28 Jakub Jelinek <jakub@redhat.com>
* c.opt (-std=c++2a, -std=c++20, -std=gnu++2a, -std=gnu++20): Remove
draft from description.
(-std=c++2b): Fix a pasto, 2020 -> 2023.
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