[LICM] Avoind store sinking if no preheader is available

Load instructions are inserted into loop preheaders when sinking stores
and later removed if not used by the SSA updater. Avoid sinking if the
loop has no preheader and avoid crashes. This fixes one more side effect
of not handling indirectbr instructions properly on LoopSimplify.

llvm-svn: 223119

1 files changed, 33 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LICM/sinking.ll b/llvm/test/Transforms/LICM/sinking.ll
index f01367b01aa..d7a8fcdafca 100644
--- a/llvm/test/Transforms/LICM/sinking.ll
+++ b/llvm/test/Transforms/LICM/sinking.ll
@@ -359,6 +359,39 @@ lab22:
   indirectbr i8* undef, [label %lab5, label %lab6, label %lab7]
 }
 
+; Test that we don't crash when trying to sink stores and there's no preheader
+; available (which is used for creating loads that may be used by the SSA
+; updater)
+define void @test13() {
+; CHECK-LABEL: @test13
+  br label %lab59
+
+lab19:
+  br i1 undef, label %lab20, label %lab38
+
+lab20:
+  br label %lab60
+
+lab21:
+  br i1 undef, label %lab22, label %lab38
+
+lab22:
+  br label %lab38
+
+lab38:
+  ret void
+
+lab59:
+  indirectbr i8* undef, [label %lab60, label %lab38]
+
+lab60:
+; CHECK: lab60:
+; CHECK: store
+; CHECK-NEXT: indirectbr
+  store i32 2145244101, i32* undef, align 4
+  indirectbr i8* undef, [label %lab21, label %lab19]
+}
+
 declare void @f(i32*)
 
 declare void @g()