Subzero: Allow deeper levels of variable splitting.

src/IceInst.cpp

Index: src/IceInst.cpp
diff --git a/src/IceInst.cpp b/src/IceInst.cpp
index f9cfdddf60c13b41771fd4a9fa80dd6d46edd2db..af1b6e19b664ee7f9442ec68188d948e578d3500 100644
--- a/src/IceInst.cpp
+++ b/src/IceInst.cpp
@@ -1094,9 +1094,14 @@ bool checkForRedundantAssign(const Variable *Dest, const Operand *Source) {
     // upper 32 bits of rax. We need to recognize and preserve these.
     return true;
   }
-  if (!Dest->hasReg() && !SrcVar->hasReg() &&
-      Dest->getStackOffset() == SrcVar->getStackOffset())
-    return true;
+  if (!Dest->hasReg() && !SrcVar->hasReg()) {
+    if (!Dest->hasStackOffset() || !SrcVar->hasStackOffset()) {
+      return false;
+    }
+    if (Dest->getStackOffset() == SrcVar->getStackOffset()) {

[John, 2016/07/06 16:07:39]

I would do:

if (Dest.StackOffset != Src.StackOffset)
  return false;

return true;

up to you

[Jim Stichnoth, 2016/07/08 10:37:54]

Done.

+      return true;
+    }
+  }
   return false;
 }