llvm-project

Commit Graph

Author	SHA1	Message	Date
Florian Hahn	14ef87bda6	[ValueTracking] usub(a, b) cannot overflow if a >= b. If we know that a >= b (unsigned), usub.with.overflow(a, b) cannot overflow. Similarly, if b > a, the same expression overflows. Reviewers: nikic, RKSimon, lebedev.ri, spatel Reviewed By: nikic, Gerolf Differential Revision: https://reviews.llvm.org/D74066	2020-02-07 10:41:18 +00:00
Florian Hahn	89ca4b9ef2	[InstCombine] Precommit usub.with.overflow test for D74066.	2020-02-07 10:30:28 +00:00

Author

SHA1

Message

Date

Florian Hahn

14ef87bda6

[ValueTracking] usub(a, b) cannot overflow if a >= b.

If we know that a >= b (unsigned), usub.with.overflow(a, b) cannot
overflow. Similarly, if b > a, the same expression overflows.

Reviewers: nikic, RKSimon, lebedev.ri, spatel

Reviewed By: nikic, Gerolf

Differential Revision: https://reviews.llvm.org/D74066

2020-02-07 10:41:18 +00:00

Florian Hahn

89ca4b9ef2

[InstCombine] Precommit usub.with.overflow test for D74066.

2020-02-07 10:30:28 +00:00

2 Commits