2 Commits

Author	SHA1	Message	Date
Roman Lebedev	aaf6ab4410	[InstSimplify] Drop leftover "division-by-zero guard" around `@llvm.umul.with.overflow` overflow bit ... Summary: Now that with D65143/D65144 we've produce `@llvm.umul.with.overflow`, and with D65147 we've flattened the CFG, we now can see that the guard may have been there to prevent division by zero is redundant. We can simply drop it: ``` ---------------------------------------- Name: no overflow and not zero %iszero = icmp ne i4 %y, 0 %umul = umul_overflow i4 %x, %y %umul.ov = extractvalue {i4, i1} %umul, 1 %retval.0 = and i1 %iszero, %umul.ov ret i1 %retval.0 => %iszero = icmp ne i4 %y, 0 %umul = umul_overflow i4 %x, %y %umul.ov = extractvalue {i4, i1} %umul, 1 %retval.0 = and i1 %iszero, %umul.ov ret %umul.ov Done: 1 Optimization is correct! ``` Reviewers: nikic, spatel, xbolva00 Reviewed By: spatel Subscribers: hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65150 llvm-svn: 370350	2019-08-29 12:47:50 +00:00
Roman Lebedev	0689427280	[InstSimplify][NFC] Tests for skipping 'div-by-0' checks before @llvm.umul.with.overflow ... These may remain after @llvm.umul.with.overflow was canonicalized from the code that was originally doing the check via division. llvm-svn: 366751	2019-07-22 22:09:11 +00:00