[llvm] 5599c43 - GlobalISel: Swap order of operand checks in ConstantFoldVectorBinop

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2022-01-18T17:21:02-05:00
New Revision: 5599c43124c5ba70738494466ea3dc722759274c

URL: https://github.com/llvm/llvm-project/commit/5599c43124c5ba70738494466ea3dc722759274c
DIFF: https://github.com/llvm/llvm-project/commit/5599c43124c5ba70738494466ea3dc722759274c.diff

LOG: GlobalISel: Swap order of operand checks in ConstantFoldVectorBinop

Since constants are canonicalized to the RHS, this is more likely to
exit early.

Added: 
    

Modified: 
    llvm/lib/CodeGen/GlobalISel/Utils.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
index 5cdf9be16c06..544af9a2954f 100644
--- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -596,13 +596,14 @@ Register llvm::ConstantFoldVectorBinop(unsigned Opcode, const Register Op1,
                                        const Register Op2,
                                        const MachineRegisterInfo &MRI,
                                        MachineIRBuilder &MIB) {
-  auto *SrcVec1 = getOpcodeDef<GBuildVector>(Op1, MRI);
-  if (!SrcVec1)
-    return Register();
   auto *SrcVec2 = getOpcodeDef<GBuildVector>(Op2, MRI);
   if (!SrcVec2)
     return Register();
 
+  auto *SrcVec1 = getOpcodeDef<GBuildVector>(Op1, MRI);
+  if (!SrcVec1)
+    return Register();
+
   const LLT EltTy = MRI.getType(SrcVec1->getSourceReg(0));
 
   SmallVector<Register, 16> FoldedElements;