Fix a crash in InstCombine where we could try to truncate a switch co…

…mparison to zero width. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231761 91177308-0d34-0410-b5e6-96231b3b80d8
babooppa6 · Mar 10, 2015 · 3a3665f · 3a3665f
1 parent bb6a88c
commit 3a3665f
Show file tree

Hide file tree

Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2060,7 +2060,8 @@ Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
   // x86 generates redundant zero-extenstion instructions if the operand is
   // truncated to i8 or i16.
   bool TruncCond = false;
-  if (BitWidth > NewWidth && NewWidth >= DL.getLargestLegalIntTypeSize()) {
+  if (NewWidth > 0 && BitWidth > NewWidth &&
+      NewWidth >= DL.getLargestLegalIntTypeSize()) {
     TruncCond = true;
     IntegerType *Ty = IntegerType::get(SI.getContext(), NewWidth);
     Builder->SetInsertPoint(&SI);

diff --git a/test/Transforms/InstCombine/switch-truncate-crash.ll b/test/Transforms/InstCombine/switch-truncate-crash.ll
@@ -0,0 +1,7 @@
+; RUN: opt -instcombine < %s
+
+define void @test() {
+  switch i32 0, label %out [i32 0, label %out]
+out:
+  ret void
+}