llvm-project

Commit Graph

Author	SHA1	Message	Date
Bill Wendling	6d2714738f	The DAG combiner was performing a BT combine. The BT combine had a value of -1, so it changed it into a 31 via the TLO.ShrinkDemandedConstant() call. Then it would go through the DAG combiner again. This time it had a value of 31, which was turned into a -1 by TLI.SimplifyDemandedBits(). This would ping pong forever. Teach the TLO.ShrinkDemandedConstant() call not to lower a value if the demanded value is an XOR of all ones. llvm-svn: 65985	2009-03-04 00:18:06 +00:00

Author

SHA1

Message

Date

Bill Wendling

6d2714738f

The DAG combiner was performing a BT combine. The BT combine had a value of -1,

so it changed it into a 31 via the TLO.ShrinkDemandedConstant() call. Then it
would go through the DAG combiner again. This time it had a value of 31, which
was turned into a -1 by TLI.SimplifyDemandedBits(). This would ping pong
forever.

Teach the TLO.ShrinkDemandedConstant() call not to lower a value if the demanded
value is an XOR of all ones.

llvm-svn: 65985

2009-03-04 00:18:06 +00:00

1 Commits