Minor optimization: when doing eq/ne comparions and RHS is a constant - swap operands...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89574 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/MSP430/MSP430ISelLowering.cpp b/lib/Target/MSP430/MSP430ISelLowering.cpp
index adc6d58961ee378ea6f9fefdc9534173b39fcdf4..29cc370bef99020770a6f5e9de572e894ceaa41b 100644 (file)
--- a/lib/Target/MSP430/MSP430ISelLowering.cpp
+++ b/lib/Target/MSP430/MSP430ISelLowering.cpp
@@ -594,9 +594,17 @@ static SDValue EmitCMP(SDValue &LHS, SDValue &RHS, SDValue &TargetCC,
   default: llvm_unreachable("Invalid integer condition!");
   case ISD::SETEQ:
     TCC = MSP430CC::COND_E;     // aka COND_Z
+    // Minor optimization: if RHS is a constant, swap operands, then the
+    // constant can be folded into comparison.
+    if (RHS.getOpcode() == ISD::Constant)
+      std::swap(LHS, RHS);
     break;
   case ISD::SETNE:
     TCC = MSP430CC::COND_NE;    // aka COND_NZ
+    // Minor optimization: if RHS is a constant, swap operands, then the
+    // constant can be folded into comparison.
+    if (RHS.getOpcode() == ISD::Constant)
+      std::swap(LHS, RHS);
     break;
   case ISD::SETULE:
     std::swap(LHS, RHS);        // FALLTHROUGH