3 Commits

Author	SHA1	Message	Date
Sanjay Patel	e9a153f414	[InstCombine] add unsigned saturation subtraction canonicalizations ... This is the instcombine part of unsigned saturation canonicalization. Backend patches already commited: https://reviews.llvm.org/D37510 https://reviews.llvm.org/D37534 It converts unsigned saturated subtraction patterns to forms recognized by the backend: (a > b) ? a - b : 0 -> ((a > b) ? a : b) - b) (b < a) ? a - b : 0 -> ((a > b) ? a : b) - b) (b > a) ? 0 : a - b -> ((a > b) ? a : b) - b) (a < b) ? 0 : a - b -> ((a > b) ? a : b) - b) ((a > b) ? b - a : 0) -> - ((a > b) ? a : b) - b) ((b < a) ? b - a : 0) -> - ((a > b) ? a : b) - b) ((b > a) ? 0 : b - a) -> - ((a > b) ? a : b) - b) ((a < b) ? 0 : b - a) -> - ((a > b) ? a : b) - b) Patch by Yulia Koval! Differential Revision: https://reviews.llvm.org/D41480 llvm-svn: 324255	2018-02-05 17:53:29 +00:00
Sanjay Patel	a767ee5af0	[InstCombine] make sure tests are providing coverage for the stated pattern; NFC ... Without extra instructions and uses, swapMayExposeCSEOpportunities() would change the icmp (as seen in the check lines), so we were not actually testing patterns that should be handled by D41480. llvm-svn: 324143	2018-02-02 21:40:54 +00:00
Sanjay Patel	5b8cb26bcc	[InstCombine] add baseline tests for unsigned saturated sub (D41480); NFC ... llvm-svn: 324109	2018-02-02 17:43:16 +00:00