Don't do code sinking on unreachable blocks. It's unprofitable and hazardous.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100455 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/unreachable-loop-sinking.ll b/test/CodeGen/X86/unreachable-loop-sinking.ll
new file mode 100644
index 0000000..35f6917
--- /dev/null
+++ b/test/CodeGen/X86/unreachable-loop-sinking.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s
+; PR6777
+
+; MachineSink shouldn't try to sink code in unreachable blocks, as it's
+; not worthwhile, and there are corner cases which it doesn't handle.
+
+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"
+target triple = "x86_64-unknown-linux-gnu"
+
+define double @fn1(i8* %arg, i64 %arg1) {
+Entry:
+ br i1 undef, label %Body, label %Exit
+
+Exit: ; preds = %Brancher7, %Entry
+ ret double undef
+
+Body: ; preds = %Entry
+ br i1 false, label %Brancher7, label %Body3
+
+Body3: ; preds = %Body6, %Body3, %Body
+ br label %Body3
+
+Body6: ; preds = %Brancher7
+ %tmp = fcmp oeq double 0xC04FBB2E40000000, undef ; <i1> [#uses=1]
+ br i1 %tmp, label %Body3, label %Brancher7
+
+Brancher7: ; preds = %Body6, %Body
+ %tmp2 = icmp ult i32 undef, 10 ; <i1> [#uses=1]
+ br i1 %tmp2, label %Body6, label %Exit
+}