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| author | Uros Bizjak <ubizjak@gmail.com> | 2020-05-04 13:49:14 +0200 |
|---|---|---|
| committer | Uros Bizjak <ubizjak@gmail.com> | 2020-05-04 13:49:14 +0200 |
| commit | 8ea03e9016cbca5a7ee2b4befa4d5c32467b0982 (patch) | |
| tree | 67d23af3275c8c5a39a516143abe17d843b0c210 /gcc/tree-ssa-loop-im.c | |
| parent | 6b5c7ee0df6b87780f2fd6f2c5759a04e6eed1fe (diff) | |
| download | gcc-8ea03e9016cbca5a7ee2b4befa4d5c32467b0982.zip gcc-8ea03e9016cbca5a7ee2b4befa4d5c32467b0982.tar.gz gcc-8ea03e9016cbca5a7ee2b4befa4d5c32467b0982.tar.bz2 | |
i386: Use SHR to compare with large power-of-two constants [PR94650]
Convert unsigned compares where
m >= LARGE_POWER_OF_TWO
and LARGE_POWER_OF_TWO represent an immediate where bit 33+ is set to use
a SHR instruction and compare the result to 0. This avoids loading a
large immediate with MOVABS insn.
movabsq $1099511627775, %rax
cmpq %rax, %rdi
ja .L5
gets converted to:
shrq $40, %rdi
jne .L5
PR target/94650
* config/i386/predicates.md (shr_comparison_operator): New predicate.
* config/i386/i386.md (compare->shr splitter): New splitters.
testsuite/ChangeLog:
PR target/94650
* gcc.targeti/i386/pr94650.c: New test.
Diffstat (limited to 'gcc/tree-ssa-loop-im.c')
0 files changed, 0 insertions, 0 deletions