Fix a bug in FoldSelectOpOp. Bitcast ops may change the number of vector elements...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158166 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 0ae00ea17a8fbafd70626bb8281f333d522ea0be..eb9945b681727c913418d5520b59253e41ca9209 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -129,6 +129,12 @@ Instruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI,
     if (TI->isCast()) {
       if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType())
         return 0;
+      // The select condition may be a vector. We may only change the operand
+      // type if the vector width remains the same (and matches the condition).
+      Type *CondTy = SI.getCondition()->getType();
+      if (CondTy->isVectorTy() && CondTy->getVectorNumElements() !=
+          FI->getOperand(0)->getType()->getVectorNumElements())
+        return 0;
     } else {
       return 0;  // unknown unary op.
     }

diff --git a/test/Transforms/InstCombine/2012-6-7-vselect-bitcast.ll b/test/Transforms/InstCombine/2012-6-7-vselect-bitcast.ll
new file mode 100644 (file)
index 0000000..cb527f8
--- /dev/null
+++ b/test/Transforms/InstCombine/2012-6-7-vselect-bitcast.ll
@@ -0,0 +1,11 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+; CHECK: bitcast
+
+define void @foo(<16 x i8> %a, <16 x i8> %b, <4 x i32>* %c) {
+  %aa = bitcast <16 x i8> %a to <4 x i32>
+  %bb = bitcast <16 x i8> %b to <4 x i32>
+  %select_v = select <4 x i1> zeroinitializer, <4 x i32> %aa, <4 x i32> %bb
+  store <4 x i32> %select_v, <4 x i32>* %c, align 4
+  ret void
+}
+