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| author | Jeffrey A Law <law@cygnus.com> | 1998-07-05 23:20:51 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1998-07-05 17:20:51 -0600 |
| commit | adc05e6ce6c535b2dcc218e0486dd6298f5c7ba8 (patch) | |
| tree | 056a0913eaa34a61e6187fe35692e5edf7e3f130 | |
| parent | 80de1662849972bc92c9081a2baf8c2723ac27d9 (diff) | |
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combine.c (simplify_comparison): Do not commute a AND into a paradoxical SUBREG if not WORD_REGISTER_OPERATIONS.
* combine.c (simplify_comparison): Do not commute a AND into
a paradoxical SUBREG if not WORD_REGISTER_OPERATIONS.
From-SVN: r20934
| -rw-r--r-- | gcc/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/combine.c | 10 |
2 files changed, 13 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e91a7e0..8e9c2e4 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,8 @@ Sun Jul 5 23:58:19 1998 Jeffrey A Law (law@cygnus.com) + * combine.c (simplify_comparison): Do not commute a AND into + a paradoxical SUBREG if not WORD_REGISTER_OPERATIONS. + * i386/freebsd-elf.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Protect with HAVE_GAS_MAX_SKIP_P2ALIGN. * i386/linux.h: Likewise. diff --git a/gcc/combine.c b/gcc/combine.c index a0c7864..a299fb0 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10154,6 +10154,16 @@ simplify_comparison (code, pop0, pop1) || subreg_lowpart_p (XEXP (op0, 0)) #endif ) +#ifndef WORD_REGISTER_OPERATIONS + /* It is unsafe to commute the AND into the SUBREG if the SUBREG + is paradoxical and WORD_REGISTER_OPERATIONS is not defined. + As originally written the upper bits have a defined value + due to the AND operation. However, if we commute the AND + inside the SUBREG then they no longer have defined values + and the meaning of the code has been changed. */ + && (GET_MODE_SIZE (GET_MODE (XEXP (op0, 0))) + <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0))))) +#endif && GET_CODE (XEXP (op0, 1)) == CONST_INT && mode_width <= HOST_BITS_PER_WIDE_INT && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0)))) |