[VectorCombine] foldShuffleToIdentity - ensure casts have the same source type

Author: RKSimon

llvm/lib/Transforms/Vectorize/VectorCombine.cpp

@@ -1906,6 +1906,9 @@ bool VectorCombine::foldShuffleToIdentity(Instruction &I) {
           if (auto *CI = dyn_cast<CmpInst>(V))
             if (CI->getPredicate() != cast<CmpInst>(FrontV)->getPredicate())
               return false;
+          if (auto *CI = dyn_cast<CastInst>(V))
+            if (CI->getSrcTy() != cast<CastInst>(FrontV)->getSrcTy())
+              return false;
           if (auto *SI = dyn_cast<SelectInst>(V))
             if (!isa<VectorType>(SI->getOperand(0)->getType()) ||
                 SI->getOperand(0)->getType() !=

llvm/test/Transforms/VectorCombine/AArch64/shuffletoidentity.ll

@@ -993,6 +993,25 @@ define void @maximal_legal_fpmath(ptr %addr1, ptr %addr2, ptr %result, float %va
   ret void
 }
 
+define void @bitcast_srcty_mismatch() {
+; CHECK-LABEL: @bitcast_srcty_mismatch(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[SHUFFLE_I_I:%.*]] = shufflevector <2 x i64> zeroinitializer, <2 x i64> zeroinitializer, <2 x i32> <i32 1, i32 3>
+; CHECK-NEXT:    [[TMP0:%.*]] = bitcast <4 x i32> zeroinitializer to <4 x float>
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast <2 x i64> [[SHUFFLE_I_I]] to <4 x float>
+; CHECK-NEXT:    [[SHUFP_I196:%.*]] = shufflevector <4 x float> [[TMP0]], <4 x float> [[TMP1]], <4 x i32> <i32 2, i32 1, i32 4, i32 7>
+; CHECK-NEXT:    store <4 x float> [[SHUFP_I196]], ptr null, align 16
+; CHECK-NEXT:    ret void
+;
+entry:
+  %shuffle.i.i = shufflevector <2 x i64> zeroinitializer, <2 x i64> zeroinitializer, <2 x i32> <i32 1, i32 3>
+  %0 = bitcast <4 x i32> zeroinitializer to <4 x float>
+  %1 = bitcast <2 x i64> %shuffle.i.i to <4 x float>
+  %shufp.i196 = shufflevector <4 x float> %0, <4 x float> %1, <4 x i32> <i32 2, i32 1, i32 4, i32 7>
+  store <4 x float> %shufp.i196, ptr null, align 16
+  ret void
+}
+
 define <2 x float> @first_scalar_select(<2 x float> %0, <2 x float> %1, float %x) {
 ; CHECK-LABEL: @first_scalar_select(
 ; CHECK-NEXT:  entry: