From 7b8481b330720d28c019a2e5994492a1923d5daa Mon Sep 17 00:00:00 2001 From: "Paul A. Clarke" Date: Thu, 19 Sep 2019 11:11:04 -0500 Subject: [powerpc] No need to enter "Ignore Exceptions Mode" Since at least POWER8, there is no performance advantage to entering "Ignore Exceptions Mode", and doing so conditionally requires - the conditional logic, and - a system call. Make it a no-op for uses within glibc. --- sysdeps/powerpc/fpu/fenv_private.h | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'sysdeps/powerpc/fpu') diff --git a/sysdeps/powerpc/fpu/fenv_private.h b/sysdeps/powerpc/fpu/fenv_private.h index 5eedc3b552..4af767b965 100644 --- a/sysdeps/powerpc/fpu/fenv_private.h +++ b/sysdeps/powerpc/fpu/fenv_private.h @@ -23,6 +23,17 @@ #include #include +#ifdef _ARCH_PWR8 +/* There is no performance advantage to non-stop mode. */ +/* The odd syntax here is to innocuously reference the given variables + to prevent warnings about unused variables. */ +#define __TEST_AND_BEGIN_NON_STOP(old, new) do {} while ((old) * (new) * 0 != 0) +#define __TEST_AND_END_NON_STOP(old, new) do {} while ((old) * (new) * 0 != 0) +#else +#define __TEST_AND_BEGIN_NON_STOP __TEST_AND_ENTER_NON_STOP +#define __TEST_AND_END_NON_STOP __TEST_AND_EXIT_NON_STOP +#endif + static __always_inline void libc_feholdexcept_setround_ppc (fenv_t *envp, int r) { @@ -30,7 +41,7 @@ libc_feholdexcept_setround_ppc (fenv_t *envp, int r) old.fenv = *envp = fegetenv_register (); - __TEST_AND_ENTER_NON_STOP (old.l, 0ULL); + __TEST_AND_BEGIN_NON_STOP (old.l, 0ULL); /* Clear everything and set the rounding mode. */ new.l = r; @@ -49,8 +60,8 @@ __libc_femergeenv_ppc (const fenv_t *envp, unsigned long long old_mask, /* Merge bits while masking unwanted bits from new and old env. */ new.l = (old.l & old_mask) | (new.l & new_mask); - __TEST_AND_EXIT_NON_STOP (old.l, new.l); - __TEST_AND_ENTER_NON_STOP (old.l, new.l); + __TEST_AND_END_NON_STOP (old.l, new.l); + __TEST_AND_BEGIN_NON_STOP (old.l, new.l); /* If requesting to keep status, replace control, and merge exceptions, and exceptions haven't changed, we can just set new control instead @@ -141,7 +152,7 @@ libc_feholdsetround_noex_ppc_ctx (struct rm_ctx *ctx, int r) ctx->env = old.fenv; if (__glibc_unlikely (new.l != old.l)) { - __TEST_AND_ENTER_NON_STOP (old.l, 0ULL); + __TEST_AND_BEGIN_NON_STOP (old.l, 0ULL); fesetenv_control (new.fenv); ctx->updated_status = true; } -- cgit v1.2.3