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| author | Reid Kleckner <reid@kleckner.net> | 2014-03-27 17:49:27 +0000 |
|---|---|---|
| committer | Reid Kleckner <reid@kleckner.net> | 2014-03-27 17:49:27 +0000 |
| commit | 3bdf9bc48b9e2b678882ade29ee1fb4db69f134c (patch) | |
| tree | 1e35dcaee0866c875c48c4de716e7e8df5789f04 /llvm/test/Transforms | |
| parent | 3a571019c8b17e6f5896c5b2a80e3a854011eb32 (diff) | |
| download | bcm5719-llvm-3bdf9bc48b9e2b678882ade29ee1fb4db69f134c.tar.gz bcm5719-llvm-3bdf9bc48b9e2b678882ade29ee1fb4db69f134c.zip | |
InstCombine: Don't combine constants on unsigned icmps
Fixes a miscompile introduced in r204912. It would miscompile code like
(unsigned)(a + -49) <= 5U. The transform would turn this into
(unsigned)a < 55U, which would return true for values in [0, 49], when
it should not.
llvm-svn: 204948
Diffstat (limited to 'llvm/test/Transforms')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/icmp.ll | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll index 2e3ff24f6ba..63fefc08776 100644 --- a/llvm/test/Transforms/InstCombine/icmp.ll +++ b/llvm/test/Transforms/InstCombine/icmp.ll @@ -1409,3 +1409,13 @@ entry: %conv = zext i1 %cmp to i32 ret i32 %conv } + +; CHECK-LABEL: icmp_add_const_ult +; CHECK: %cmp = icmp ult i32 %add, 6 +define i32 @icmp_add_const_ult(i32 %a) #0 { +entry: + %add = add nsw i32 %a, -49 + %cmp = icmp ult i32 %add, 6 + %conv = zext i1 %cmp to i32 + ret i32 %conv +} |
