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Commit Graph

Author	SHA1	Message	Date
Benjamin Kramer	25ad783322	Update test. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136170 91177308-0d34-0410-b5e6-96231b3b80d8	2011-07-26 22:45:39 +00:00
Benjamin Kramer	162ee5c725	Add a neat little two's complement hack for x86. On x86 we can't encode an immediate LHS of a sub directly. If the RHS comes from a XOR with a constant we can fold the negation into the xor and add one to the immediate of the sub. Then we can turn the sub into an add, which can be commuted and encoded efficiently. This code is generated for __builtin_clz and friends. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136167 91177308-0d34-0410-b5e6-96231b3b80d8	2011-07-26 22:42:13 +00:00

Author

SHA1

Message

Date

Benjamin Kramer

25ad783322

Update test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136170 91177308-0d34-0410-b5e6-96231b3b80d8

2011-07-26 22:45:39 +00:00

Benjamin Kramer

162ee5c725

Add a neat little two's complement hack for x86.

On x86 we can't encode an immediate LHS of a sub directly. If the RHS comes from a XOR with a constant we can
fold the negation into the xor and add one to the immediate of the sub. Then we can turn the sub into an add,
which can be commuted and encoded efficiently.

This code is generated for __builtin_clz and friends.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136167 91177308-0d34-0410-b5e6-96231b3b80d8

2011-07-26 22:42:13 +00:00

2 Commits