Fixed a register scavenger bug. If a def is re-defining part of a super register, there must be an implicit def of the super-register on the MI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48024 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 3 deletions

diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index 635e0cc825..2535d78cd9 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -29,15 +29,20 @@ using namespace llvm;
 /// part of a super-register.
 static bool RedefinesSuperRegPart(const MachineInstr *MI, unsigned SubReg,
                                   const TargetRegisterInfo *TRI) {
+  bool SeenSuperUse = false;
+  bool SeenSuperDef = false;
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI->getOperand(i);
-    if (!MO.isRegister() || !MO.isUse())
+    if (!MO.isRegister())
       continue;
     if (TRI->isSuperRegister(SubReg, MO.getReg()))
-      return true;
+      if (MO.isUse())
+        SeenSuperUse = true;
+      else if (MO.isImplicit())
+        SeenSuperDef = true;
   }
 
-  return false;
+  return SeenSuperDef && SeenSuperUse;
 }
 
 static bool RedefinesSuperRegPart(const MachineInstr *MI,