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| author | Richard Henderson <rth@cygnus.com> | 1999-12-16 01:42:57 -0800 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1999-12-16 02:42:57 -0700 |
| commit | 0bd4b46174e402c4ac0da5235f4d5a066662e80a (patch) | |
| tree | 4b4c3de06f5bc7eb77643be40e61c0348ad5ca95 /gcc | |
| parent | 41adf8980c131b99320448577776c8bfce3f2282 (diff) | |
| download | gcc-0bd4b46174e402c4ac0da5235f4d5a066662e80a.zip gcc-0bd4b46174e402c4ac0da5235f4d5a066662e80a.tar.gz gcc-0bd4b46174e402c4ac0da5235f4d5a066662e80a.tar.bz2 | |
combine.c (simplify_comparison): Reduce (OP (MINUS A B) 0) to (OP A B).
* combine.c (simplify_comparison): Reduce (OP (MINUS A B) 0)
to (OP A B).
From-SVN: r30970
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/combine.c | 8 |
2 files changed, 13 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index acce2bf..35343e3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +Thu Dec 16 02:41:26 1999 Richard Henderson (rth@cygnus.com) + + * combine.c (simplify_comparison): Reduce (OP (MINUS A B) 0) + to (OP A B). + Thu Dec 16 02:26:11 1999 Jeffrey A Law (law@cygnus.com) * h8300.md (HImode preinc peephole): Fix typo. diff --git a/gcc/combine.c b/gcc/combine.c index 5dc4fc8..3599168 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10320,6 +10320,14 @@ simplify_comparison (code, pop0, pop1) break; case MINUS: + /* (op (minus A B) 0) -> (op A B) */ + if (op1 == const0_rtx) + { + op1 = XEXP (op0, 1); + op0 = XEXP (op0, 0); + continue; + } + /* (eq (minus A B) C) -> (eq A (plus B C)) or (eq B (minus A C)), whichever simplifies. We can only do this for equality comparisons due to pathological cases involving |