| Summary: | [tree-ssa] Convert (x < 0) || (y < 0) into (x | y) < 0. | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Kazu Hirata <kazu> |
| Component: | tree-optimization | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | enhancement | CC: | allen_1985624, dimhen, gabravier, gcc-bugs, jeffreyalaw, zhongyunde |
| Priority: | P2 | Keywords: | missed-optimization |
| Version: | tree-ssa | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | 2005-12-30 22:22:49 | |
| Bug Depends on: | 15357, 15459 | ||
| Bug Blocks: | 19987 | ||
Another one just like above:
void bar (void);
void
foo (int a, int b)
{
if (a != 0)
return;
if (b != 0)
return;
bar ();
}
void
baz (int a, int b)
{
if ((a | b) == 0)
bar ();
}
See also PR 15241.
Confirmed. For AMD64, the functions from the first test case don't produce the same code either, so combine is not catching this either. x86_64 r10-7080 for me produce identical code -- c#0 with -O2 -- c#1 with -O Resolved at some point in the past. Not worth the trouble to bisect. |
Convert foo() into baz(). void bar (void); int foo (int x, int y) { int t1 = x < 0; int t2 = y < 0; return t1 || t2; } int baz (int x, int y) { return (x | y) < 0; } Needless to mention, we should do this fairly late in SSA optimizations.