llvm-project

Author SHA1 Message Date

Author	SHA1	Message	Date
Kai Luo	f6515b0520	[PowerPC] Do not fold `cmp(d\|w)` and `subf` instruction to `subf.` if `nsw` is not present In `PPCInstrInfo::optimizeCompareInstr` we seek opportunities to fold `cmp(d\|w)` and `subf` as an `subf.`. However, if `subf.` gets overflow, `cr0` can't reflect the correct order, violating the semantics of `cmp(d\|w)`. Fixed https://bugs.llvm.org/show_bug.cgi?id=47830. Reviewed By: #powerpc, nemanjai Differential Revision: https://reviews.llvm.org/D90156	2021-01-04 07:54:15 +00:00
Kai Luo	82150dae86	[PowerPC] Add test case for pr47830. NFC.	2020-10-26 09:11:33 +00:00

Kai Luo

f6515b0520

[PowerPC] Do not fold cmp(d|w) and subf instruction to subf. if nsw is not present

In `PPCInstrInfo::optimizeCompareInstr` we seek opportunities to fold `cmp(d|w)` and `subf` as an `subf.`. However, if `subf.` gets overflow, `cr0` can't reflect the correct order, violating the semantics of `cmp(d|w)`.

Fixed https://bugs.llvm.org/show_bug.cgi?id=47830.

Reviewed By: #powerpc, nemanjai

Differential Revision: https://reviews.llvm.org/D90156

2021-01-04 07:54:15 +00:00

Kai Luo

82150dae86

[PowerPC] Add test case for pr47830. NFC.

2020-10-26 09:11:33 +00:00

2 Commits