Fix PR7096. When a block containing multiple defs is tail duplicated, the

SSAUpdater for the value from the first def may see uses of undefined values,
because the later defs will not have been updated yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103407 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/MachineSSAUpdater.cpp b/lib/CodeGen/MachineSSAUpdater.cpp
index 99fb99ac3c72254b40d69a724616a972e831398b..84d6df25397c5eb2d854df768c01ca962f472e12 100644 (file)
--- a/lib/CodeGen/MachineSSAUpdater.cpp
+++ b/lib/CodeGen/MachineSSAUpdater.cpp
@@ -329,7 +329,7 @@ public:
   /// InstrIsPHI - Check if an instruction is a PHI.
   ///
   static MachineInstr *InstrIsPHI(MachineInstr *I) {
-    if (I->isPHI())
+    if (I && I->isPHI())
       return I;
     return 0;
   }