[HLSL] Fix Root signature test error (llvm#127261)

Fixing error detected in build bot in file
`RootSignature-MultipleEntryFunctions.ll`

closes: [127260](llvm#127260)

---------

Co-authored-by: joaosaffran <joao.saffran@microsoft.com>

Author: 2 people

llvm/lib/Target/DirectX/DXILRootSignature.cpp

@@ -186,20 +186,23 @@ PreservedAnalyses RootSignatureAnalysisPrinter::run(Module &M,
   OS << "Root Signature Definitions"
      << "\n";
   uint8_t Space = 0;
-  for (const auto &P : RSDMap) {
-    const auto &[Function, RSD] = P;
-    OS << "Definition for '" << Function->getName() << "':\n";
+  for (const Function &F : M) {
+    auto It = RSDMap.find(&F);
+    if (It == RSDMap.end())
+      continue;
+    const auto &RS = It->second;
+    OS << "Definition for '" << F.getName() << "':\n";
 
     // start root signature header
     Space++;
-    OS << indent(Space) << "Flags: " << format_hex(RSD.Flags, 8) << ":\n";
-    OS << indent(Space) << "Version: " << RSD.Version << ":\n";
-    OS << indent(Space) << "NumParameters: " << RSD.NumParameters << ":\n";
-    OS << indent(Space) << "RootParametersOffset: " << RSD.RootParametersOffset
+    OS << indent(Space) << "Flags: " << format_hex(RS.Flags, 8) << ":\n";
+    OS << indent(Space) << "Version: " << RS.Version << ":\n";
+    OS << indent(Space) << "NumParameters: " << RS.NumParameters << ":\n";
+    OS << indent(Space) << "RootParametersOffset: " << RS.RootParametersOffset
        << ":\n";
-    OS << indent(Space) << "NumStaticSamplers: " << RSD.NumStaticSamplers
+    OS << indent(Space) << "NumStaticSamplers: " << RS.NumStaticSamplers
        << ":\n";
-    OS << indent(Space) << "StaticSamplersOffset: " << RSD.StaticSamplersOffset
+    OS << indent(Space) << "StaticSamplersOffset: " << RS.StaticSamplersOffset
        << ":\n";
     Space--;
     // end root signature header

llvm/test/CodeGen/DirectX/ContainerData/RootSignature-MultipleEntryFunctions.ll

@@ -23,7 +23,6 @@ attributes #0 = { "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
 !6 = !{ !7 } ; list of root signature elements
 !7 = !{ !"RootFlags", i32 2 } ; 1 = allow_input_assembler_input_layout
 
-
 ; CHECK-LABEL: Definition for 'main':
 ; CHECK-NEXT:   Flags: 0x000001
 ; CHECK-NEXT:   Version: 2