[PATCH] D18830: [llvm] GVN.cpp: Do not swap when both LHS and RHS are arguments.

[Aditya Kumar via llvm-commits]

hiraditya created this revision.
hiraditya added reviewers: chandlerc, mcrosier, joker.eph, sebpop.
hiraditya added a subscriber: llvm-commits.
hiraditya set the repository for this revision to rL LLVM.

Prevent swapping of operands when both LHS and RHS are arguments.
Passes llvm regression

Repository:
  rL LLVM

http://reviews.llvm.org/D18830

Files:
  llvm/lib/Transforms/Scalar/GVN.cpp

Index: llvm/lib/Transforms/Scalar/GVN.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GVN.cpp
+++ llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1892,7 +1892,8 @@
       continue;
 
     // Prefer a constant on the right-hand side, or an Argument if no constants.
-    if (isa<Constant>(LHS) || (isa<Argument>(LHS) && !isa<Constant>(RHS)))
+    if (isa<Constant>(LHS)
+        || (isa<Argument>(LHS) && !isa<Argument>(RHS) && !isa<Constant>(RHS)))
       std::swap(LHS, RHS);
     assert((isa<Argument>(LHS) || isa<Instruction>(LHS)) && "Unexpected value!");
 


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