| Summary: | GCC 12 miscompiles libm | ||
|---|---|---|---|
| Product: | glibc | Reporter: | H.J. Lu <hjl.tools> |
| Component: | math | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | jwakely.gcc |
| Priority: | P2 | ||
| Version: | 2.35 | ||
| Target Milestone: | 2.35 | ||
| See Also: | https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103735 | ||
| Host: | Target: | ||
| Build: | Last reconfirmed: | ||
|
Description
H.J. Lu
2021-12-18 23:10:27 UTC
Fixed by commit 6e30181b4a3ab6c56da0378b65f4d60504982300 Author: H.J. Lu <hjl.tools@gmail.com> Date: Mon Dec 20 15:00:24 2021 -0800 math: Properly cast X_TLOSS to float [BZ #28713] Add #define AS_FLOAT_CONSTANT_1(x) x##f #define AS_FLOAT_CONSTANT(x) AS_FLOAT_CONSTANT_1(x) to cast X_TLOSS to float at compile-time to fix: FAIL: math/test-float-j0 FAIL: math/test-float-jn FAIL: math/test-float-y0 FAIL: math/test-float-y1 FAIL: math/test-float-yn FAIL: math/test-float32-j0 FAIL: math/test-float32-jn FAIL: math/test-float32-y0 FAIL: math/test-float32-y1 FAIL: math/test-float32-yn when compiling with GCC 12. Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr> And by commit d3e4f5a1014db09ff1c62c6506f92cba469e193d Author: H.J. Lu <hjl.tools@gmail.com> Date: Mon Dec 20 14:37:26 2021 -0800 s_sincosf.h: Change pio4 type to float [BZ #28713] s_cosf.c and s_sinf.c have if (abstop12 (y) < abstop12 (pio4)) where abstop12 takes a float argument, but pio4 is static const double. pio4 is used only in calls to abstop12 and never in arithmetic. Apply -static const double pio4 = 0x1.921FB54442D18p-1; +static const float pio4 = 0x1.921FB6p-1f; to fix: FAIL: math/test-float-cos FAIL: math/test-float-sin FAIL: math/test-float-sincos FAIL: math/test-float32-cos FAIL: math/test-float32-sin FAIL: math/test-float32-sincos when compiling with GCC 12. Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr> The master branch has been updated by Szabolcs Nagy <nsz@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=347a5b592c91f0230d52a5117fd83e1f75028207 commit 347a5b592c91f0230d52a5117fd83e1f75028207 Author: Szabolcs Nagy <szabolcs.nagy@arm.com> Date: Fri Dec 31 09:50:50 2021 +0000 math: Fix float conversion regressions with gcc-12 [BZ #28713] Converting double precision constants to float is now affected by the runtime dynamic rounding mode instead of being evaluated at compile time with default rounding mode (except static object initializers). This can change the computed result and cause performance regression. The known correctness issues (increased ulp errors) are already fixed, this patch fixes remaining cases of unnecessary runtime conversions. Add float M_* macros to math.h as new GNU extension API. To avoid conversions the new M_* macros are used and instead of casting double literals to float, use float literals (only required if the conversion is inexact). The patch was tested on aarch64 where the following symbols had new spurious conversion instructions that got fixed: __clog10f __gammaf_r_finite@GLIBC_2.17 __j0f_finite@GLIBC_2.17 __j1f_finite@GLIBC_2.17 __jnf_finite@GLIBC_2.17 __kernel_casinhf __lgamma_negf __log1pf __y0f_finite@GLIBC_2.17 __y1f_finite@GLIBC_2.17 cacosf cacoshf casinhf catanf catanhf clogf gammaf_positive Fixes bug 28713. Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr> This breaks any C++ program using those names, e.g. see https://bugzilla.redhat.com/show_bug.cgi?id=2045149#c6 This is because G++ always defines _GNU_SOURCE. Was this considered? (In reply to Jonathan Wakely from comment #4) > This breaks any C++ program using those names, e.g. see > https://bugzilla.redhat.com/show_bug.cgi?id=2045149#c6 > > This is because G++ always defines _GNU_SOURCE. > > Was this considered? Filed as PR 28963 |