[llvm] 6ea7437 - [SelectionDAG] Bail out of mergeTruncStores when not optimizing

[Arthur Eubanks via llvm-commits]

Author: Arthur Eubanks
Date: 2021-10-20T16:58:22-07:00
New Revision: 6ea7437ca5a4f8aff895d940cd8b0e5b65419f86

URL: https://github.com/llvm/llvm-project/commit/6ea7437ca5a4f8aff895d940cd8b0e5b65419f86
DIFF: https://github.com/llvm/llvm-project/commit/6ea7437ca5a4f8aff895d940cd8b0e5b65419f86.diff

LOG: [SelectionDAG] Bail out of mergeTruncStores when not optimizing

With unoptimized code, we may see lots of stores and spend too much time in mergeTruncStores.

Fixes PR51827.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D111596

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5f656ece0e5c..4686ee0b41b4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7315,7 +7315,7 @@ SDValue DAGCombiner::mergeTruncStores(StoreSDNode *N) {
   // TODO: If there is evidence that running this later would help, this
   //       limitation could be removed. Legality checks may need to be added
   //       for the created store and optional bswap/rotate.
-  if (LegalOperations)
+  if (LegalOperations || OptLevel == CodeGenOpt::None)
     return SDValue();
 
   // We only handle merging simple stores of 1-4 bytes.