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authorBill Wendling <isanbard@gmail.com>2011-03-30 21:37:19 +0000
committerBill Wendling <isanbard@gmail.com>2011-03-30 21:37:19 +0000
commit31d244ead52171632cc4649623b426dbea27040a (patch)
tree6c74281dac484b04c931ddd355f895457781c4f9
parent81bd78b89779704aeb762f51c6c19b06d542b6d6 (diff)
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* The DSE code that tested for overlapping needed to take into account the fact
that one of the numbers is signed while the other is unsigned. This could lead to a wrong result when the signed was promoted to an unsigned int. * Add the data layout line to the testcase so that it will test the appropriate thing. Patch by David Terei! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128577 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/Transforms/Scalar/DeadStoreElimination.cpp4
-rw-r--r--test/Transforms/DeadStoreElimination/2011-03-25-DSEMiscompile.ll1
2 files changed, 4 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp
index f473cf5..9f36a38 100644
--- a/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -361,8 +361,10 @@ static bool isCompleteOverwrite(const AliasAnalysis::Location &Later,
//
// |--earlier--|
// |----- later ------|
+ //
+ // We have to be careful here as *Off is signed while *.Size is unsigned.
if (EarlierOff >= LaterOff &&
- EarlierOff + Earlier.Size <= LaterOff + Later.Size)
+ uint64_t(EarlierOff - LaterOff) + Earlier.Size <= Later.Size)
return true;
// Otherwise, they don't completely overlap.
diff --git a/test/Transforms/DeadStoreElimination/2011-03-25-DSEMiscompile.ll b/test/Transforms/DeadStoreElimination/2011-03-25-DSEMiscompile.ll
index e268dd5..079eec4 100644
--- a/test/Transforms/DeadStoreElimination/2011-03-25-DSEMiscompile.ll
+++ b/test/Transforms/DeadStoreElimination/2011-03-25-DSEMiscompile.ll
@@ -1,5 +1,6 @@
; RUN: opt < %s -basicaa -dse -S | FileCheck %s
; PR9561
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
target triple = "i386-apple-darwin9.8"
@A = external global [0 x i32]