Revert "[llvm][IR] Extend BranchWeightMetadata to track provenance of weights" (#95060)

Reverts llvm/llvm-project#86609

This change causes compile-time regressions for stage2 builds
(https://llvm-compile-time-tracker.com/compare.php?from=3254f31a66263ea9647c9547f1531c3123444fcd&to=c5978f1eb5eeca8610b9dfce1fcbf1f473911cd8&stat=instructions:u).
It also introduced unintended changes to `.text` which should be
addressed before relanding.

1 files changed, 10 insertions, 13 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 107c8bb..292739b 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -861,28 +861,26 @@ static bool ValuesOverlap(std::vector<ValueEqualityComparisonCase> &C1,
 
 // Set branch weights on SwitchInst. This sets the metadata if there is at
 // least one non-zero weight.
-static void setBranchWeights(SwitchInst *SI, ArrayRef<uint32_t> Weights,
-                             bool IsExpected) {
+static void setBranchWeights(SwitchInst *SI, ArrayRef<uint32_t> Weights) {
   // Check that there is at least one non-zero weight. Otherwise, pass
   // nullptr to setMetadata which will erase the existing metadata.
   MDNode *N = nullptr;
   if (llvm::any_of(Weights, [](uint32_t W) { return W != 0; }))
-    N = MDBuilder(SI->getParent()->getContext())
-            .createBranchWeights(Weights, IsExpected);
+    N = MDBuilder(SI->getParent()->getContext()).createBranchWeights(Weights);
   SI->setMetadata(LLVMContext::MD_prof, N);
 }
 
 // Similar to the above, but for branch and select instructions that take
 // exactly 2 weights.
 static void setBranchWeights(Instruction *I, uint32_t TrueWeight,
-                             uint32_t FalseWeight, bool IsExpected) {
+                             uint32_t FalseWeight) {
   assert(isa<BranchInst>(I) || isa<SelectInst>(I));
   // Check that there is at least one non-zero weight. Otherwise, pass
   // nullptr to setMetadata which will erase the existing metadata.
   MDNode *N = nullptr;
   if (TrueWeight || FalseWeight)
     N = MDBuilder(I->getParent()->getContext())
-            .createBranchWeights(TrueWeight, FalseWeight, IsExpected);
+            .createBranchWeights(TrueWeight, FalseWeight);
   I->setMetadata(LLVMContext::MD_prof, N);
 }
 
@@ -1340,7 +1338,7 @@ bool SimplifyCFGOpt::PerformValueComparisonIntoPredecessorFolding(
 
     SmallVector<uint32_t, 8> MDWeights(Weights.begin(), Weights.end());
 
-    setBranchWeights(NewSI, MDWeights, /*IsExpected=*/false);
+    setBranchWeights(NewSI, MDWeights);
   }
 
   EraseTerminatorAndDCECond(PTI);
@@ -3833,7 +3831,7 @@ static bool performBranchToCommonDestFolding(BranchInst *BI, BranchInst *PBI,
     FitWeights(NewWeights);
 
     SmallVector<uint32_t, 8> MDWeights(NewWeights.begin(), NewWeights.end());
-    setBranchWeights(PBI, MDWeights[0], MDWeights[1], /*IsExpected=*/false);
+    setBranchWeights(PBI, MDWeights[0], MDWeights[1]);
 
     // TODO: If BB is reachable from all paths through PredBlock, then we
     // could replace PBI's branch probabilities with BI's.
@@ -4570,7 +4568,7 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
     // Halve the weights if any of them cannot fit in an uint32_t
     FitWeights(NewWeights);
 
-    setBranchWeights(PBI, NewWeights[0], NewWeights[1], /*IsExpected=*/false);
+    setBranchWeights(PBI, NewWeights[0], NewWeights[1]);
   }
 
   // OtherDest may have phi nodes.  If so, add an entry from PBI's
@@ -4606,8 +4604,7 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
 
         FitWeights(NewWeights);
 
-        setBranchWeights(NV, NewWeights[0], NewWeights[1],
-                         /*IsExpected=*/false);
+        setBranchWeights(NV, NewWeights[0], NewWeights[1]);
       }
     }
   }
@@ -4670,7 +4667,7 @@ bool SimplifyCFGOpt::SimplifyTerminatorOnSelect(Instruction *OldTerm,
       // Create a conditional branch sharing the condition of the select.
       BranchInst *NewBI = Builder.CreateCondBr(Cond, TrueBB, FalseBB);
       if (TrueWeight != FalseWeight)
-        setBranchWeights(NewBI, TrueWeight, FalseWeight, /*IsExpected=*/false);
+        setBranchWeights(NewBI, TrueWeight, FalseWeight);
     }
   } else if (KeepEdge1 && (KeepEdge2 || TrueBB == FalseBB)) {
     // Neither of the selected blocks were successors, so this
@@ -5620,7 +5617,7 @@ bool SimplifyCFGOpt::TurnSwitchRangeIntoICmp(SwitchInst *SI,
         TrueWeight /= 2;
         FalseWeight /= 2;
       }
-      setBranchWeights(NewBI, TrueWeight, FalseWeight, /*IsExpected=*/false);
+      setBranchWeights(NewBI, TrueWeight, FalseWeight);
     }
   }