[LoopSimplify] Preserve LCSSA when removing edges from unreachable blocks.
This fixes PR30454.
llvm-svn: 287379
diff --git a/llvm/test/Transforms/LoopSimplify/pr30454.ll b/llvm/test/Transforms/LoopSimplify/pr30454.ll
new file mode 100644
index 0000000..3dcc393
--- /dev/null
+++ b/llvm/test/Transforms/LoopSimplify/pr30454.ll
@@ -0,0 +1,32 @@
+; RUN: opt < %s -lcssa -licm -S | FileCheck %s
+; PR30454
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare i8 @bar()
+
+; Test that we preserve LCSSA form when removing edges from unreachable blocks.
+; CHECK-LABEL: @foo
+define void @foo() {
+entry:
+ br label %for.cond
+
+for.cond:
+ %x = phi i8 [ undef, %entry ], [ %y, %for.latch ]
+ br i1 undef, label %for.latch, label %exit
+
+; CHECK: unreachable.bb:
+; CHECK-NEXT: unreachable
+unreachable.bb:
+ br i1 undef, label %exit, label %for.latch
+
+for.latch:
+ %y = call i8 @bar()
+ br label %for.cond
+
+; CHECK: exit:
+; CHECK-NEXT: %x.lcssa = phi i8 [ %x, %for.cond ]
+exit:
+ %z = zext i8 %x to i32
+ ret void
+}