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powerpc: Fix __fesetround_inline_nocheck on POWER9+ (BZ 31682)

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The e68b1151f7 commit changed the
__fesetround_inline_nocheck implementation to use mffscrni
(through __fe_mffscrn) instead of mtfsfi.  For generic powerpc
ceil/floor/trunc, the function is supposed to disable the
floating-point inexact exception enable bit, however mffscrni
does not change any exception enable bits.

This patch fixes by reverting the optimization for the
__fesetround_inline_nocheck.

Checked on powerpc-linux-gnu.
Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>
This commit is contained in:
Adhemerval Zanella 2024-05-07 09:19:48 -03:00
parent dd5f891c1a
commit ae515ba530
2 changed files with 8 additions and 14 deletions
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16
sysdeps/powerpc/fpu/fenv_libc.h
View file

@ -182,19 +182,13 @@ __fesetround_inline (int round)
return 0; return 0;
} }
/* Same as __fesetround_inline, however without runtime check to use DFP /* Same as __fesetround_inline, and it also disable the floating-point
mtfsfi syntax (as relax_fenv_state) or if round value is valid. */ inexact execption (bit 60 - XE, assuming NI is 0). It does not check
if ROUND is a valid value. */
static inline void static inline void
__fesetround_inline_nocheck (const int round) __fesetround_inline_disable_inexact (const int round)
{ {
#ifdef _ARCH_PWR9 asm volatile ("mtfsfi 7,%0" : : "n" (round));
__fe_mffscrn (round);
#else
if (__glibc_likely (GLRO(dl_hwcap2) & PPC_FEATURE2_ARCH_3_00))
__fe_mffscrn (round);
else
asm volatile ("mtfsfi 7,%0" : : "n" (round));
#endif
} }
#define FPSCR_MASK(bit) (1 << (31 - (bit))) #define FPSCR_MASK(bit) (1 << (31 - (bit)))

6
sysdeps/powerpc/fpu/round_to_integer.h
View file

@ -42,14 +42,14 @@ set_fenv_mode (enum round_mode mode)
switch (mode) switch (mode)
{ {
case CEIL: case CEIL:
__fesetround_inline_nocheck (FE_UPWARD); __fesetround_inline_disable_inexact (FE_UPWARD);
break; break;
case FLOOR: case FLOOR:
__fesetround_inline_nocheck (FE_DOWNWARD); __fesetround_inline_disable_inexact (FE_DOWNWARD);
break; break;
case TRUNC: case TRUNC:
case ROUND: case ROUND:
__fesetround_inline_nocheck (FE_TOWARDZERO); __fesetround_inline_disable_inexact (FE_TOWARDZERO);
break; break;
case NEARBYINT: case NEARBYINT:
/* Disable FE_INEXACT exception */ /* Disable FE_INEXACT exception */