llvm-project

Commit Graph

Author	SHA1	Message	Date
Sanjay Patel	a1067d9bae	[BDCE] reduce scope of an assert (PR34179) The assert was added with r310779 and is usually correct, but as the test shows, not always. The 'volatile' on the load is needed to expose the faulty path because without it, DemandedBits would return that the load is just dead rather than not demanded, and so we wouldn't hit the bogus assert. Also, since the lambda is just a single-line now, get rid of it and inline the DB.isAllOnesValue() calls. This should fix (prevent execution of a faulty assert): https://bugs.llvm.org/show_bug.cgi?id=34179 llvm-svn: 310842	2017-08-14 15:13:46 +00:00
Sanjay Patel	fe346f9f5b	[BDCE] clear poison generators after turning a value into zero (PR33695, PR34037) nsw, nuw, and exact carry implicit assumptions about their operands, so we need to clear those after trivializing a value. We decided there was no danger for llvm.assume or metadata, so there's just a comment about that. This fixes miscompiles as shown in: https://bugs.llvm.org/show_bug.cgi?id=33695 https://bugs.llvm.org/show_bug.cgi?id=34037 Differential Revision: https://reviews.llvm.org/D36592 llvm-svn: 310779	2017-08-12 16:41:08 +00:00
Sanjay Patel	c0fc1c0c8b	[BDCE] add tests to show invalid/incomplete transforms llvm-svn: 309945	2017-08-03 15:07:37 +00:00

Author

SHA1

Message

Date

Sanjay Patel

a1067d9bae

[BDCE] reduce scope of an assert (PR34179)

The assert was added with r310779 and is usually correct,
but as the test shows, not always. The 'volatile' on the
load is needed to expose the faulty path because without
it, DemandedBits would return that the load is just dead
rather than not demanded, and so we wouldn't hit the
bogus assert.

Also, since the lambda is just a single-line now, get rid 
of it and inline the DB.isAllOnesValue() calls. 

This should fix (prevent execution of a faulty assert):
https://bugs.llvm.org/show_bug.cgi?id=34179

llvm-svn: 310842

2017-08-14 15:13:46 +00:00

Sanjay Patel

fe346f9f5b

[BDCE] clear poison generators after turning a value into zero (PR33695, PR34037)

nsw, nuw, and exact carry implicit assumptions about their operands, so we need
to clear those after trivializing a value. We decided there was no danger for
llvm.assume or metadata, so there's just a comment about that.

This fixes miscompiles as shown in:
https://bugs.llvm.org/show_bug.cgi?id=33695
https://bugs.llvm.org/show_bug.cgi?id=34037

Differential Revision: https://reviews.llvm.org/D36592

llvm-svn: 310779

2017-08-12 16:41:08 +00:00

Sanjay Patel

c0fc1c0c8b

[BDCE] add tests to show invalid/incomplete transforms

llvm-svn: 309945

2017-08-03 15:07:37 +00:00

3 Commits