llvm-6502

6502/llvm-6502

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Author	SHA1	Message	Date
Bill Wendling	36ae6c1827	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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65985 91177308-0d34-0410-b5e6-96231b3b80d8	2009-03-04 00:18:06 +00:00

Author

SHA1

Message

Date

Bill Wendling

36ae6c1827

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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65985 91177308-0d34-0410-b5e6-96231b3b80d8

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

1 Commits