[llvm] r223205 - R600/SI: Fix suspicious indexing

[Matt Arsenault]

Author: arsenm
Date: Tue Dec  2 23:22:32 2014
New Revision: 223205

URL: http://llvm.org/viewvc/llvm-project?rev=223205&view=rev
Log:
R600/SI: Fix suspicious indexing

The loop is over the operands of an instruction, and checks the
register with the sub reg index of the dest register. This probably
meant to be checking the sub reg index of the same operand.

Modified:
    llvm/trunk/lib/Target/R600/SIFixSGPRCopies.cpp

Modified: llvm/trunk/lib/Target/R600/SIFixSGPRCopies.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/SIFixSGPRCopies.cpp?rev=223205&r1=223204&r2=223205&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/SIFixSGPRCopies.cpp (original)
+++ llvm/trunk/lib/Target/R600/SIFixSGPRCopies.cpp Tue Dec  2 23:22:32 2014
@@ -219,11 +219,13 @@ bool SIFixSGPRCopies::runOnMachineFuncti
       case AMDGPU::PHI: {
         DEBUG(dbgs() << "Fixing PHI: " << MI);
 
-        for (unsigned i = 1; i < MI.getNumOperands(); i+=2) {
-          unsigned Reg = MI.getOperand(i).getReg();
-          const TargetRegisterClass *RC = inferRegClassFromDef(TRI, MRI, Reg,
-                                                  MI.getOperand(0).getSubReg());
-          MRI.constrainRegClass(Reg, RC);
+        for (unsigned i = 1; i < MI.getNumOperands(); i += 2) {
+          const MachineOperand &Op = MI.getOperand(i);
+          unsigned Reg = Op.getReg();
+          const TargetRegisterClass *RC
+            = inferRegClassFromDef(TRI, MRI, Reg, Op.getSubReg());
+
+          MRI.constrainRegClass(Op.getReg(), RC);
         }
         unsigned Reg = MI.getOperand(0).getReg();
         const TargetRegisterClass *RC = inferRegClassFromUses(TRI, MRI, Reg,