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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
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Jeffrey A Law 1998-07-05 23:20:51 +00:00 committed by Jeff Law
parent 80de166284
commit adc05e6ce6
2 changed files with 13 additions and 0 deletions
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3
gcc/ChangeLog
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@ -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.

10
gcc/combine.c
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@ -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))))