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authorEric Christopher <echristo@gmail.com>2019-04-17 04:52:47 +0000
committerEric Christopher <echristo@gmail.com>2019-04-17 04:52:47 +0000
commitcee313d288a4faf0355d76fb6e0e927e211d08a5 (patch)
treed386075318d761197779a96e5d8fc0dc7b06342b /llvm/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll
parentc3d6a929fdd92fd06d4304675ade8d7210ee711a (diff)
downloadbcm5719-llvm-cee313d288a4faf0355d76fb6e0e927e211d08a5.tar.gz
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Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
Diffstat (limited to 'llvm/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll')
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diff --git a/llvm/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll b/llvm/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll
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+++ b/llvm/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll
@@ -0,0 +1,17 @@
+; RUN: opt < %s -instsimplify
+
+; The mul can be proved to always overflow (turning a negative value
+; into a positive one) and thus results in undefined behaviour. At
+; the same time we were deducing from the nsw flag that that mul could
+; be assumed to have a negative value (since if not it has an undefined
+; value, which can be taken to be negative). We were reporting the mul
+; as being both positive and negative, firing an assertion!
+define i1 @test1(i32 %a) {
+entry:
+ %0 = or i32 %a, 1
+ %1 = shl i32 %0, 31
+ %2 = mul nsw i32 %1, 4
+ %3 = and i32 %2, -4
+ %4 = icmp ne i32 %3, 0
+ ret i1 %4
+}
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