[PATCH] D15622: AMDGPU: fix overlapping copies in copyPhysReg

[Nicolai Hähnle via llvm-commits]

nhaehnle added inline comments.

================
Comment at: lib/Target/AMDGPU/SIInstrInfo.cpp:432-435
@@ -430,2 +431,6 @@
 
-  while (unsigned SubIdx = *SubIndices++) {
+  if (RI.getHWRegIndex(DestReg) <= RI.getHWRegIndex(SrcReg))
+    Forward = true;
+  else
+    Forward = false;
+
----------------
tstellarAMD wrote:
> Is there some reason why you used a variable here and didn't put this condition directly in the if() below?
Yes: the intention was to make it obvious that the condition is constant throughout the loop for both the human and the compiler.


http://reviews.llvm.org/D15622