address comments

Author: c-rhodes

llvm/lib/Analysis/ValueTracking.cpp

@@ -7678,9 +7678,9 @@ static bool isGuaranteedNotToBeUndefOrPoison(
         return true;
     }
 
-    Value *Splat;
     if (!::canCreateUndefOrPoison(Opr, Kind,
                                   /*ConsiderFlagsAndMetadata=*/true)) {
+      Value *Splat;
       if (const auto *PN = dyn_cast<PHINode>(V)) {
         unsigned Num = PN->getNumIncomingValues();
         bool IsWellDefined = true;

llvm/test/Transforms/InstSimplify/freeze-noundef.ll

@@ -156,3 +156,16 @@ define {i8, i32} @noundef_metadata2(ptr %p) {
   %v.fr = freeze {i8, i32} %v
   ret {i8, i32} %v.fr
 }
+
+; For splats only the poison-ness of the value being splatted matters.
+define <4 x i32> @splat(i32 noundef %x) {
+; CHECK-LABEL: @splat(
+; CHECK-NEXT:    [[INS:%.*]] = insertelement <4 x i32> poison, i32 [[X:%.*]], i32 0
+; CHECK-NEXT:    [[SPLAT:%.*]] = shufflevector <4 x i32> [[INS]], <4 x i32> poison, <4 x i32> zeroinitializer
+; CHECK-NEXT:    ret <4 x i32> [[SPLAT]]
+;
+  %ins = insertelement <4 x i32> poison, i32 %x, i32 0
+  %splat = shufflevector <4 x i32> %ins, <4 x i32> poison, <4 x i32> zeroinitializer
+  %splat.fr = freeze <4 x i32> %splat
+  ret <4 x i32> %splat.fr
+}