Fix failing test and DxilMutateResourceToHandle case hit by updated test (#4694)

DxilMutateResourceToHandle would skip GEP if result type does not need to be mutated.
But then the GEP would not have setSourceElementType called with the new source type leaving invalid IR.

The fix makes sure the GEP is added to MutateValSet when skipping recursion.

lib/HLSL/DxilPromoteResourcePasses.cpp

@@ -547,8 +547,11 @@ void DxilMutateResourceToHandle::collectCandidates(Module &M) {
         // If result type of GEP not related to resource type, skip.
         Type *Ty = GEP->getType();
         Type *MTy = mutateToHandleTy(Ty);
-        if (MTy == Ty)
+        if (MTy == Ty) {
+          // Don't recurse, but still need to mutate GEP.
+          MutateValSet.insert(GEP);
           continue;
+        }
         newCandidates.emplace_back(GEP);
       } else if (PHINode *Phi = dyn_cast<PHINode>(U)) {
         // Propagate all operands.

tools/clang/test/HLSLFileCheck/hlsl/resource_binding/resource-in-struct.hlsl

@@ -1,8 +1,12 @@
 // RUN: %dxc -E main -T ps_6_0 %s  | FileCheck %s
-// RUN: %dxc -T lib_6_7 -validator-version 1.7 %s  | FileCheck %s -check-prefixes=CHECKTYPE,CHECKNORP
-// RUN: %dxc -T lib_6_8 %s  | FileCheck %s -check-prefixes=CHECKTYPE,CHECKRP
 // RUN: %dxc -T lib_6_x %s  | FileCheck %s -check-prefixes=CHECKTYPE,CHECKRP
 
+// For now: No scenario here should produce the type annotation, since that
+// should be unused in final DXIL, and thus eliminated.  Uncomment when a
+// scenario is crafted out that should produce the annotation.
+// xUN: %dxc -T lib_6_7 -validator-version 1.7 %s  | FileCheck %s -check-prefixes=CHECKTYPE,CHECKNORP
+// xUN: %dxc -T lib_6_8 %s  | FileCheck %s -check-prefixes=CHECKTYPE,CHECKRP
+
 // CHECK: res.Tex1
 
 // Make sure ResourceProperties are emitted.
@@ -26,9 +30,14 @@ struct Resources
   float4 foo;
 };
 
-Resources res;
+Resources g_res;
 
+float4 foo(Resources res, float4 coord) {
+  return res.Tex1.Sample(Samp, coord.xy) * res.foo;
+}
+
+[shader("pixel")]
 float4 main(int4 a : A, float4 coord : TEXCOORD) : SV_TARGET
 {
-  return res.Tex1.Sample(Samp, coord.xy) * res.foo;
+  return foo(g_res, coord);
 }