5 Commits

Author	SHA1	Message	Date
Benjamin Kramer	0baa94a13b	InstCombine: Turn icmp + sext into bitwise/integer ops when the input has only one unknown bit. ... int test1(unsigned x) { return (x&8) ? 0 : -1; } int test3(unsigned x) { return (x&8) ? -1 : 0; } before (x86_64): _test1: andl $8, %edi cmpl $1, %edi sbbl %eax, %eax ret _test3: andl $8, %edi cmpl $1, %edi sbbl %eax, %eax notl %eax ret after: _test1: shrl $3, %edi andl $1, %edi leal -1(%rdi), %eax ret _test3: shll $28, %edi movl %edi, %eax sarl $31, %eax ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128732 91177308-0d34-0410-b5e6-96231b3b80d8	2011-04-01 20:09:10 +00:00
Benjamin Kramer	2715a58149	ComputeMaskedBits: sub falls through to add, and sub doesn't have the same overflow semantics as add. ... Should fix the selfhost failures that started with r127463. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127465 91177308-0d34-0410-b5e6-96231b3b80d8	2011-03-11 14:46:49 +00:00
Chris Lattner	7a6aa1a391	Enhance a bunch of transformations in instcombine to start generating ... exact/nsw/nuw shifts and have instcombine infer them when it can prove that the relevant properties are true for a given shift without them. Also, a variety of refactoring to use the new patternmatch logic thrown in for good luck. I believe that this takes care of a bunch of related code quality issues attached to PR8862. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125267 91177308-0d34-0410-b5e6-96231b3b80d8	2011-02-10 05:36:31 +00:00
Chris Lattner	edc436bbf4	merge sext-2 into sext.ll ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90293 91177308-0d34-0410-b5e6-96231b3b80d8	2009-12-02 05:34:35 +00:00
Chris Lattner	8bdcb25072	rename test ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90292 91177308-0d34-0410-b5e6-96231b3b80d8	2009-12-02 05:32:33 +00:00