[nfc][ctx_prof] Fix the second source of nondeterminism in CtxProfAnalysisPrinterPass

Verified on a build with `LLVM_REVERSE_ITERATION=ON`

Issue #106855

Author: mtrofin

llvm/include/llvm/Analysis/CtxProfAnalysis.h

@@ -25,7 +25,7 @@ class CtxProfAnalysis;
 // counter, and then, because all contexts belonging to a function have the same
 // size, there'll be at most one other heap allocation.
 using CtxProfFlatProfile =
-    DenseMap<GlobalValue::GUID, SmallVector<uint64_t, 1>>;
+    std::map<GlobalValue::GUID, SmallVector<uint64_t, 1>>;
 
 /// The instrumented contextual profile, produced by the CtxProfAnalysis.
 class PGOContextualProfile {

llvm/lib/Transforms/Instrumentation/PGOCtxProfFlattening.cpp

@@ -330,13 +330,12 @@ PreservedAnalyses PGOCtxProfFlatteningPass::run(Module &M,
            "Function has unreacheable basic blocks. The expectation was that "
            "DCE was run before.");
 
-    const auto &FlatProfile =
-        FlattenedProfile.lookup(AssignGUIDPass::getGUID(F));
+    auto It = FlattenedProfile.find(AssignGUIDPass::getGUID(F));
     // If this function didn't appear in the contextual profile, it's cold.
-    if (FlatProfile.empty())
+    if (It == FlattenedProfile.end())
       clearColdFunctionProfile(F);
     else {
-      ProfileAnnotator S(F, FlatProfile, PB);
+      ProfileAnnotator S(F, It->second, PB);
       S.assignProfileData();
     }
   }

llvm/test/Analysis/CtxProfAnalysis/full-cycle.ll

@@ -172,7 +172,7 @@ Current Profile:
 ]
 
 Flat Profile:
-10507721908651011566 : 1 
+2072045998141807037 : 7 
 3087265239403591524 : 11 9 
 4197650231481825559 : 2 
-2072045998141807037 : 7 
+10507721908651011566 : 1 

llvm/test/Analysis/CtxProfAnalysis/load.ll

@@ -90,8 +90,8 @@ Current Profile:
 
 Flat Profile:
 728453322856651412 : 6 7 
-12074870348631550642 : 5 
 11872291593386833696 : 1 
+12074870348631550642 : 5 
 ;--- example.ll
 declare void @bar()