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| author | Michael Matz <matz@gcc.gnu.org> | 2010-03-18 16:07:53 +0000 |
|---|---|---|
| committer | Michael Matz <matz@gcc.gnu.org> | 2010-03-18 16:07:53 +0000 |
| commit | c21372c41eb1f5995048a67bfc9512d860c986cb (patch) | |
| tree | 4ff7adbdf79516249e130b74195c2cb0583b9375 | |
| parent | 82fa5f8aa727db4ab9f172ddc454fc25325b82ca (diff) | |
| download | gcc-c21372c41eb1f5995048a67bfc9512d860c986cb.zip gcc-c21372c41eb1f5995048a67bfc9512d860c986cb.tar.gz gcc-c21372c41eb1f5995048a67bfc9512d860c986cb.tar.bz2 | |
re PR middle-end/43419 (gcc replaces pow(x, 0.5) by sqrt(x), invalid when x is -0)
PR middle-end/43419
* builtins.c (expand_builtin_pow): Don't transform pow(x, 0.5)
into sqrt(x) if we need to preserve signed zeros.
testsuite/
* gcc.dg/pr43419.c: New testcase.
From-SVN: r157543
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/builtins.c | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 13 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr43419.c | 19 |
4 files changed, 38 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a4254a8..31b4340 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2010-03-18 Michael Matz <matz@suse.de> + + PR middle-end/43419 + * builtins.c (expand_builtin_pow): Don't transform pow(x, 0.5) + into sqrt(x) if we need to preserve signed zeros. + 2010-03-18 Steven Bosscher <steven@gcc.gnu.org> Eric Botcazou <ebotcazou@adacore.com> diff --git a/gcc/builtins.c b/gcc/builtins.c index 1e089ef9..705a255 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -2980,7 +2980,10 @@ expand_builtin_pow (tree exp, rtx target, rtx subtarget) && ((flag_unsafe_math_optimizations && optimize_insn_for_speed_p () && powi_cost (n/2) <= POWI_MAX_MULTS) - || n == 1)) + /* Even the c==0.5 case cannot be done unconditionally + when we need to preserve signed zeros, as + pow (-0, 0.5) is +0, while sqrt(-0) is -0. */ + || (!HONOR_SIGNED_ZEROS (mode) && n == 1))) { tree call_expr = build_call_nofold (fn, 1, narg0); /* Use expand_expr in case the newly built call expression diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 4b69cb7..4a0ef16 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2010-03-18 Michael Matz <matz@suse.de> + + PR middle-end/43419 + * gcc.dg/pr43419.c: New testcase. + 2010-03-18 H.J. Lu <hongjiu.lu@intel.com> PR rtl-optimization/43360 @@ -16,10 +21,10 @@ 2010-03-17 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libfortran/43265 - *gfortran.dg/read_empty_file.f: New test. - *gfortran.dg/read_eof_all.f90: New test. - *gfortran.dg/namelist_27.f90: Eliminate infinite loop posibility. - *gfortran.dg/namelist_28.f90: Eliminate infinite loop posibility. + * gfortran.dg/read_empty_file.f: New test. + * gfortran.dg/read_eof_all.f90: New test. + * gfortran.dg/namelist_27.f90: Eliminate infinite loop posibility. + * gfortran.dg/namelist_28.f90: Eliminate infinite loop posibility. 2010-03-17 Michael Matz <matz@suse.de> diff --git a/gcc/testsuite/gcc.dg/pr43419.c b/gcc/testsuite/gcc.dg/pr43419.c new file mode 100644 index 0000000..a4306f0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr43419.c @@ -0,0 +1,19 @@ +/* { dg-do run } */ +/* { dg-options "-O1" } */ +/* { dg-add-options ieee } */ +#include <math.h> + +extern void abort (void); +void __attribute__((noinline)) f (double x) +{ + double pluszero = pow (x, 0.5); + double minuszero = sqrt (x); + if (signbit (pluszero) == signbit (minuszero)) + abort (); +} + +int main(void) +{ + f (-0.0); + return 0; +} |