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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-25 17:32:40 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-03-25 17:32:40 +0000 |
| commit | ef7b8d9e5a66f411b396b4ae8fc6b6640ffb2ba8 (patch) | |
| tree | 0ba21d928c1f435af2289e57bc3f6fbdbc827cb5 /lib/Target/README.txt | |
| parent | 6c3891067b6e2e2aa399a57ecae407677f22391d (diff) | |
| download | llvm-ef7b8d9e5a66f411b396b4ae8fc6b6640ffb2ba8.tar.gz llvm-ef7b8d9e5a66f411b396b4ae8fc6b6640ffb2ba8.tar.bz2 llvm-ef7b8d9e5a66f411b396b4ae8fc6b6640ffb2ba8.tar.xz | |
Add a note.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128286 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/README.txt')
| -rw-r--r-- | lib/Target/README.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 33941f451a..99616b47c8 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -2238,4 +2238,23 @@ missed cases: //===---------------------------------------------------------------------===// +define i1 @test1(i32 %x) nounwind { + %and = and i32 %x, 3 + %cmp = icmp ult i32 %and, 2 + ret i1 %cmp +} + +Can be folded to (x & 2) == 0. + +define i1 @test2(i32 %x) nounwind { + %and = and i32 %x, 3 + %cmp = icmp ugt i32 %and, 1 + ret i1 %cmp +} +Can be folded to (x & 2) != 0. + +SimplifyDemandedBits shrinks the "and" constant to 2 but instcombine misses the +icmp transform. + +//===---------------------------------------------------------------------===// |