Teach ConstantFolding to do a better job when folding gep(bitcast).
This permits the devirtualization of llvm.org/PR3100#c9 when compiled by clang.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90099 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 8d60907..96f738e 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -564,6 +564,7 @@
// we eliminate over-indexing of the notional static type array bounds.
// This makes it easy to determine if the getelementptr is "inbounds".
// Also, this helps GlobalOpt do SROA on GlobalVariables.
+ Ptr = cast<Constant>(Ptr->stripPointerCasts());
const Type *Ty = Ptr->getType();
SmallVector<Constant*, 32> NewIdxs;
do {
diff --git a/test/Transforms/InstCombine/getelementptr.ll b/test/Transforms/InstCombine/getelementptr.ll
index 285e0ba..de325f6 100644
--- a/test/Transforms/InstCombine/getelementptr.ll
+++ b/test/Transforms/InstCombine/getelementptr.ll
@@ -445,7 +445,7 @@
i8* getelementptr (%t1* bitcast (%t0* @s to %t1*), i32 0, i32 1, i32 0)) nounwind
ret i32 0
; CHECK: @test35
-; CHECK: call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([17 x i8]* @"\01LC8", i64 0, i64 0), i8* bitcast (i8** getelementptr (%t1* bitcast (%t0* @s to %t1*), i64 1, i32 0) to i8*)) nounwind
+; CHECK: call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([17 x i8]* @"\01LC8", i64 0, i64 0), i8* getelementptr inbounds (%t0* @s, i64 0, i32 1, i64 0)) nounwind
}
; Instcombine should constant-fold the GEP so that indices that have