do not try to analyze bitcasts from i64 to <2 x i32> in ComputedMaskedBits. While

we could do this, doing so requires adjusting the demanded mask and the code isn't
doing that yet.  This fixes PR4495

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74699 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 7509e91bdc8561c0081ee678526d7b967fdbc45c..07a18fe4de42ee59e09fc8e4a35f0efd739a3787 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -249,7 +249,10 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask,
   }
   case Instruction::BitCast: {
     const Type *SrcTy = I->getOperand(0)->getType();
-    if (SrcTy->isInteger() || isa<PointerType>(SrcTy)) {
+    if ((SrcTy->isInteger() || isa<PointerType>(SrcTy)) &&
+        // TODO: For now, not handling conversions like:
+        // (bitcast i64 %x to <2 x i32>)
+        !isa<VectorType>(I->getType())) {
       ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, TD,
                         Depth+1);
       return;

diff --git a/test/Transforms/InstCombine/2009-07-02-MaskedIntVector.ll b/test/Transforms/InstCombine/2009-07-02-MaskedIntVector.ll
new file mode 100644 (file)
index 0000000..7505de1
--- /dev/null
+++ b/test/Transforms/InstCombine/2009-07-02-MaskedIntVector.ll
@@ -0,0 +1,15 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis
+; PR4495
+
+define i32 @test(i64 %test) {
+entry:
+       %0 = bitcast <4 x i32> undef to <16 x i8>               ; <<16 x i8>> [#uses=1]
+       %t12 = shufflevector <16 x i8> %0, <16 x i8> zeroinitializer, <16 x i32> <i32 0, i32 16, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0>              ; <<16 x i8>> [#uses=1]
+       %t11 = bitcast <16 x i8> %t12 to <2 x i64>              ; <<2 x i64>> [#uses=1]
+       %t9 = extractelement <2 x i64> %t11, i32 0              ; <i64> [#uses=1]
+       %t10 = bitcast i64 %t9 to <2 x i32>             ; <<2 x i32>> [#uses=1]
+       %t7 = bitcast i64 %test to <2 x i32>            ; <<2 x i32>> [#uses=1]
+       %t6 = xor <2 x i32> %t10, %t7           ; <<2 x i32>> [#uses=1]
+       %t1 = extractelement <2 x i32> %t6, i32 0               ; <i32> [#uses=1]
+       ret i32 %t1
+}