fix PR9017, a bug where we'd assert when promoting in unreachable

code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124100 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 23 insertions, 0 deletions

diff --git a/lib/Transforms/Utils/SSAUpdater.cpp b/lib/Transforms/Utils/SSAUpdater.cpp
index 0474a7842d..3896d9851b 100644
--- a/lib/Transforms/Utils/SSAUpdater.cpp
+++ b/lib/Transforms/Utils/SSAUpdater.cpp
@@ -469,6 +469,9 @@ run(const SmallVectorImpl<Instruction*> &Insts) const {
     LoadInst *ALoad = LiveInLoads[i];
     Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent());
     replaceLoadWithValue(ALoad, NewVal);
+
+    // Avoid assertions in unreachable code.
+    if (NewVal == ALoad) NewVal = UndefValue::get(NewVal->getType());
     ALoad->replaceAllUsesWith(NewVal);
     ReplacedLoads[ALoad] = NewVal;
   }
diff --git a/test/Transforms/ScalarRepl/crash.ll b/test/Transforms/ScalarRepl/crash.ll
new file mode 100644
index 0000000000..7198e671fa
--- /dev/null
+++ b/test/Transforms/ScalarRepl/crash.ll
@@ -0,0 +1,20 @@
+; RUN: opt -scalarrepl %s -disable-output
+; RUN: opt -scalarrepl-ssa %s -disable-output
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin10.0.0"
+
+; PR9017
+define void @test1() nounwind readnone ssp {
+entry:
+  %l_72 = alloca i32*, align 8
+  unreachable
+
+for.cond:                                         ; preds = %for.cond
+  %tmp1.i = load i32** %l_72, align 8
+  store i32* %tmp1.i, i32** %l_72, align 8
+  br label %for.cond
+
+if.end:                                           ; No predecessors!
+  ret void
+}