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| author | Richard Biener <rguenther@suse.de> | 2022-01-25 11:55:28 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-01-25 12:22:30 +0100 |
| commit | 2e211a02290f3b3533b56c593fc7b95edb8593b0 (patch) | |
| tree | 10fa414be8c6b4859f546c81295cae36bca4059c /gcc/builtins.cc | |
| parent | ab2a2457780d224343ce05e7d8e2964c6a47fd83 (diff) | |
| download | gcc-2e211a02290f3b3533b56c593fc7b95edb8593b0.zip gcc-2e211a02290f3b3533b56c593fc7b95edb8593b0.tar.gz gcc-2e211a02290f3b3533b56c593fc7b95edb8593b0.tar.bz2 | |
tree-optimization/104214 - amend PR100740 fix for pointer compares
When we have a pointer relational compare we have stronger guarantees
about overflow, in particular rewriting BASE0 + STEP0 cmp BASE1 + STEP1
as BASE0 + STEP0 - STEP1 cmp BASE1 is always valid and the new IV0
does not overflow. The patch basically reverts the previous change
when pointers are involved, keeping only the more conservative handling
for equality compares which can involve comparing different object
addresses.
2022-01-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/104214
* tree-ssa-loop-niter.cc (number_of_iterations_cond): Use
stronger guarantees for relational pointer compares when
rewriting BASE0 + STEP0 cmp BASE1 + STEP1 as
BASE0 + STEP0 - STEP1 cmp BASE1.
* gcc.dg/vect/pr81196-2.c: New variant testcase only
requiring vect_int.
Diffstat (limited to 'gcc/builtins.cc')
0 files changed, 0 insertions, 0 deletions