commit ab358bfd0994b6c2b57e37be26869a611dc8fdd5
author Daniel Sanders <daniel_l_sanders@apple.com> Thu Oct 04 21:44:32 2018 +0000
committer Daniel Sanders <daniel_l_sanders@apple.com> Thu Oct 04 21:44:32 2018 +0000
tree 64f450fe2b8464602294cd16756be3b9ba87628a
parent bf378b808ae19fa709bb5babf5bcfd65a6688cb6

[globalisel][combine] Fix a rare crash when encountering an instruction whose op0 isn't a reg

The simplest instance of this is an intrinsic with no results which will have the
intrinsic ID as operand 0.

Also fix some benign incorrectness when op0 is a reg but isn't a def that was
guarded against by checking for the extension opcodes.

llvm-svn: 343821

llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp

diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index 06f0ea5..fe68c04 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -60,12 +60,8 @@
                                   unsigned OpcodeForCandidate,
                                   MachineInstr *MIForCandidate) {
   if (!CurrentUse.Ty.isValid()) {
-    if (CurrentUse.ExtendOpcode == OpcodeForCandidate)
-      return {TyForCandidate, OpcodeForCandidate, MIForCandidate};
-    if (CurrentUse.ExtendOpcode == TargetOpcode::G_ANYEXT &&
-        (OpcodeForCandidate == TargetOpcode::G_SEXT ||
-         OpcodeForCandidate == TargetOpcode::G_ZEXT ||
-         OpcodeForCandidate == TargetOpcode::G_ANYEXT))
+    if (CurrentUse.ExtendOpcode == OpcodeForCandidate ||
+        CurrentUse.ExtendOpcode == TargetOpcode::G_ANYEXT)
       return {TyForCandidate, OpcodeForCandidate, MIForCandidate};
     return CurrentUse;
   }
@@ -171,10 +167,12 @@
   PreferredTuple Preferred = {LLT(), PreferredOpcode, nullptr};
   for (auto &UseMI : MRI.use_instructions(LoadValue.getReg())) {
     if (UseMI.getOpcode() == TargetOpcode::G_SEXT ||
-        UseMI.getOpcode() == TargetOpcode::G_ZEXT || !Preferred.Ty.isValid())
+        UseMI.getOpcode() == TargetOpcode::G_ZEXT ||
+        UseMI.getOpcode() == TargetOpcode::G_ANYEXT) {
       Preferred = ChoosePreferredUse(Preferred,
                                      MRI.getType(UseMI.getOperand(0).getReg()),
                                      UseMI.getOpcode(), &UseMI);
+    }
   }
 
   // There were no extends