| commit | 59119253b3133b30114194a04171f9d353b5c7f7 | |
| author | Uros Bizjak <ubizjak@gmail.com> | |
| Fri, 29 Apr 2022 11:27:48 +0000 (29 13:27 +0200) | ||
| committer | Uros Bizjak <ubizjak@gmail.com> | |
| Fri, 29 Apr 2022 11:31:12 +0000 (29 13:31 +0200) | ||
| tree | 105aa73678b251a054964c0602875c73a40ef3f7 | treesnapshot (tar.gz zip) |
| parent | c090743b2ae0095f792371c7cbeb3cf6e2978f5d | commitdiff |
i386: Optimize double-word negation [PR51954]
Introduce peephole2 pattern to convert from:
mov %esi, %edx
negl %eax
adcl $0, %edx
negl %edx
to:
xorl %edx, %edx
negl %eax
sbbl %esi, %edx
This conversion is profitable only when initial move is found. Otherwise,
additional move to a temporary together with clearing xor is needed.
2022-04-29 Uroš Bizjak <ubizjak@gmail.com>
gcc/ChangeLog:
PR target/51954
* config/i386/i386.md (adcl/neg -> sbb peephole): New peephole2.
gcc/testsuite/ChangeLog:
PR target/51954
* gcc.target/i386/pr51954.c: New test.
Introduce peephole2 pattern to convert from:
mov %esi, %edx
negl %eax
adcl $0, %edx
negl %edx
to:
xorl %edx, %edx
negl %eax
sbbl %esi, %edx
This conversion is profitable only when initial move is found. Otherwise,
additional move to a temporary together with clearing xor is needed.
2022-04-29 Uroš Bizjak <ubizjak@gmail.com>
gcc/ChangeLog:
PR target/51954
* config/i386/i386.md (adcl/neg -> sbb peephole): New peephole2.
gcc/testsuite/ChangeLog:
PR target/51954
* gcc.target/i386/pr51954.c: New test.
| gcc/config/i386/i386.md | diffblobblamehistory | |
| gcc/testsuite/gcc.target/i386/pr51954.c | [new file with mode: 0644] | blob |