mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-03-11 20:27:30 +08:00
Code Issues Packages Projects Releases Wiki Activity

combine.c (simplify_comparison): Do not commute a AND into a paradoxical SUBREG if not WORD_REGISTER_OPERATIONS.

Browse Source 
* combine.c (simplify_comparison): Do not commute a AND into
	a paradoxical SUBREG if not WORD_REGISTER_OPERATIONS.

From-SVN: r20934
This commit is contained in:
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
gcc/ChangeLog
View File

@ -1,5 +1,8 @@
Sun Jul 5 23:58:19 1998 Jeffrey A Law (law@cygnus.com) 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 * i386/freebsd-elf.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Protect with
HAVE_GAS_MAX_SKIP_P2ALIGN. HAVE_GAS_MAX_SKIP_P2ALIGN.
* i386/linux.h: Likewise. * i386/linux.h: Likewise.

10
gcc/combine.c
View File

@ -10154,6 +10154,16 @@ simplify_comparison (code, pop0, pop1)
|| subreg_lowpart_p (XEXP (op0, 0)) || subreg_lowpart_p (XEXP (op0, 0))
#endif #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 && GET_CODE (XEXP (op0, 1)) == CONST_INT
&& mode_width <= HOST_BITS_PER_WIDE_INT && mode_width <= HOST_BITS_PER_WIDE_INT
&& (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0)))) && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (XEXP (op0, 0))))