[llvm] dab1e30 - [SimplifyCFG][NFC] Renumber blocks when changing func (#186666)

[via llvm-commits]

Author: Alexis Engelke
Date: 2026-03-15T16:45:01+01:00
New Revision: dab1e30d39fec6c17e0e5a8dd1d2a3dbb2a9aa96

URL: https://github.com/llvm/llvm-project/commit/dab1e30d39fec6c17e0e5a8dd1d2a3dbb2a9aa96
DIFF: https://github.com/llvm/llvm-project/commit/dab1e30d39fec6c17e0e5a8dd1d2a3dbb2a9aa96.diff

LOG: [SimplifyCFG][NFC] Renumber blocks when changing func (#186666)

Keep numbering dense when changing the function. SimplifyCFG is a good
candidate, because it is likely to remove blocks and preserves few
analyses.

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index e790ab8ac1df5..debf033c70c41 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -380,9 +380,13 @@ PreservedAnalyses SimplifyCFGPass::run(Function &F,
     DT = &AM.getResult<DominatorTreeAnalysis>(F);
   if (!simplifyFunctionCFG(F, TTI, DT, Options))
     return PreservedAnalyses::all();
+  // If we removed some blocks, update block numbers to keep dense numbering.
+  F.renumberBlocks();
   PreservedAnalyses PA;
-  if (RequireAndPreserveDomTree)
+  if (RequireAndPreserveDomTree) {
+    DT->updateBlockNumbers();
     PA.preserve<DominatorTreeAnalysis>();
+  }
   return PA;
 }