Benjamin Kramer
47a8607721
InstCombine: Teach foldLogOpOfMaskedICmpsHelper that sign bit tests are bit tests.
...
This subsumes several other transforms while enabling us to catch more cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147777 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-09 17:23:27 +00:00
Benjamin Kramer
d4242d8ab1
Tweak my last commit to be less conservative about uses.
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We still save an instruction when just the "and" part is replaced.
Also change the code to match comments more closely.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147753 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-08 21:12:51 +00:00
Benjamin Kramer
dfb806f6ba
InstCombine: If we have a bit test and a sign test anded/ored together, merge the sign bit into the bit test.
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This is common in bit field code, e.g. checking if the first or the last bit of a bit field is set.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147749 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-08 18:32:24 +00:00
Benjamin Kramer
9822b869fc
InstCombine: Add a few missing combines for ANDs and ORs of sign bit tests.
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On x86 we now compile "if (a < 0 && b < 0)" into
testl %edi, %esi
js IF.THEN
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128496 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 22:06:41 +00:00
