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authorAdam Nemet <anemet@caviumnetworks.com>2006-01-29 03:08:38 +0000
committerAdam Nemet <nemet@gcc.gnu.org>2006-01-29 03:08:38 +0000
commit1e84b34e7473adaa56186f8dad3d9db31ffd75b5 (patch)
treef96acf509bf5a7593c1f9458877f3b544574ae86 /gcc/combine.c
parent3dcf4d30e7fff3ebf0998e0fe6401719580e4d7a (diff)
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combine.c (simplify_comparison <AND>): Check TRULY_NOOP_TRUNCATION before start using a subreg.
* combine.c (simplify_comparison <AND>): Check TRULY_NOOP_TRUNCATION before start using a subreg. * config/mips/mips.md (*branch_zero<mode>, *branch_zero<mode>_inverted, *branch_equality<mode>, *branch_equality<mode>_inverted, *branch_equality<mode>_mips16): Remove mode check from comparisons. From-SVN: r110358
Diffstat (limited to 'gcc/combine.c')
-rw-r--r--gcc/combine.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/gcc/combine.c b/gcc/combine.c
index 2c90be5..ee8d98d 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -10295,14 +10295,27 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1)
/* If this AND operation is really a ZERO_EXTEND from a narrower
mode, the constant fits within that mode, and this is either an
equality or unsigned comparison, try to do this comparison in
- the narrower mode. */
+ the narrower mode.
+
+ Note that in:
+
+ (ne:DI (and:DI (reg:DI 4) (const_int 0xffffffff)) (const_int 0))
+ -> (ne:DI (reg:SI 4) (const_int 0))
+
+ unless TRULY_NOOP_TRUNCATION allows it or the register is
+ known to hold a value of the required mode the
+ transformation is invalid. */
if ((equality_comparison_p || unsigned_comparison_p)
&& GET_CODE (XEXP (op0, 1)) == CONST_INT
&& (i = exact_log2 ((INTVAL (XEXP (op0, 1))
& GET_MODE_MASK (mode))
+ 1)) >= 0
&& const_op >> i == 0
- && (tmode = mode_for_size (i, MODE_INT, 1)) != BLKmode)
+ && (tmode = mode_for_size (i, MODE_INT, 1)) != BLKmode
+ && (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (tmode),
+ GET_MODE_BITSIZE (GET_MODE (op0)))
+ || (REG_P (XEXP (op0, 0))
+ && reg_truncated_to_mode (tmode, XEXP (op0, 0)))))
{
op0 = gen_lowpart (tmode, XEXP (op0, 0));
continue;