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| author | Pan Li <pan2.li@intel.com> | 2024-01-10 20:57:17 +0800 |
|---|---|---|
| committer | Pan Li <pan2.li@intel.com> | 2024-01-11 18:35:00 +0800 |
| commit | b89ef3d40afc4604c279e8802bf279f6e4060f67 (patch) | |
| tree | feca67dc26c38d9b1c12eacc84611f829d837b4d /gcc | |
| parent | 5400778f69d19a94017561c7de02510d9c0899e6 (diff) | |
| download | gcc-b89ef3d40afc4604c279e8802bf279f6e4060f67.zip gcc-b89ef3d40afc4604c279e8802bf279f6e4060f67.tar.gz gcc-b89ef3d40afc4604c279e8802bf279f6e4060f67.tar.bz2 | |
LOOP-UNROLL: Leverage HAS_SIGNED_ZERO for var expansion
The insert_var_expansion_initialization depends on the
HONOR_SIGNED_ZEROS to initialize the unrolling variables
to +0.0f when -0.0f and no-signed-option. Unfortunately,
we should always keep the -0.0f here because:
* The -0.0f is always the correct initial value.
* We need to support the target that always honor signed zero.
Thus, we need to leverage MODE_HAS_SIGNED_ZEROS when initialize
instead of HONOR_SIGNED_ZEROS. Then the target/backend can
decide to honor the no-signed-zero or not.
We also removed the testcase pr30957-1.c, as it makes undefined behavior
whether the return value is positive or negative.
The below tests are passed for this patch:
* The riscv regression tests.
* The aarch64 regression tests.
* The x86 bootstrap and regression tests.
gcc/ChangeLog:
* loop-unroll.cc (insert_var_expansion_initialization): Leverage
MODE_HAS_SIGNED_ZEROS for expansion variable initialization.
gcc/testsuite/ChangeLog:
* gcc.dg/pr30957-1.c: Remove.
Signed-off-by: Pan Li <pan2.li@intel.com>
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/loop-unroll.cc | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr30957-1.c | 36 |
2 files changed, 2 insertions, 38 deletions
diff --git a/gcc/loop-unroll.cc b/gcc/loop-unroll.cc index 4176a21..bfdfe6c 100644 --- a/gcc/loop-unroll.cc +++ b/gcc/loop-unroll.cc @@ -1855,7 +1855,7 @@ insert_var_expansion_initialization (struct var_to_expand *ve, rtx var, zero_init; unsigned i; machine_mode mode = GET_MODE (ve->reg); - bool honor_signed_zero_p = HONOR_SIGNED_ZEROS (mode); + bool has_signed_zero_p = MODE_HAS_SIGNED_ZEROS (mode); if (ve->var_expansions.length () == 0) return; @@ -1869,7 +1869,7 @@ insert_var_expansion_initialization (struct var_to_expand *ve, case MINUS: FOR_EACH_VEC_ELT (ve->var_expansions, i, var) { - if (honor_signed_zero_p) + if (has_signed_zero_p) zero_init = simplify_gen_unary (NEG, mode, CONST0_RTX (mode), mode); else zero_init = CONST0_RTX (mode); diff --git a/gcc/testsuite/gcc.dg/pr30957-1.c b/gcc/testsuite/gcc.dg/pr30957-1.c deleted file mode 100644 index 5644109..0000000 --- a/gcc/testsuite/gcc.dg/pr30957-1.c +++ /dev/null @@ -1,36 +0,0 @@ -/* { dg-do run { xfail { mmix-*-* } } } */ -/* We don't (and don't want to) perform this optimisation on soft-float targets, - where each addition is a library call. / -/* { dg-require-effective-target hard_float } */ -/* -fassociative-math requires -fno-trapping-math and -fno-signed-zeros. */ -/* { dg-options "-O2 -funroll-loops -fassociative-math -fno-trapping-math -fno-signed-zeros -fvariable-expansion-in-unroller -fdump-rtl-loop2_unroll" } */ - -extern void abort (void); -extern void exit (int); - -float __attribute__((noinline)) -foo (float d, int n) -{ - unsigned i; - float accum = d; - - for (i = 0; i < n; i++) - accum += d; - - return accum; -} - -int -main () -{ - /* When compiling standard compliant we expect foo to return -0.0. But the - variable expansion during unrolling optimization (for this testcase enabled - by non-compliant -fassociative-math) instantiates copy(s) of the - accumulator which it initializes with +0.0. Hence we expect that foo - returns +0.0. */ - if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0) - abort (); - exit (0); -} - -/* { dg-final { scan-rtl-dump "Expanding Accumulator" "loop2_unroll" { xfail mmix-*-* } } } */ |