[ShrinkWrapping] Give up on irreducible CFGs.

[oota-llvm.git] / test / CodeGen / X86 / x86-shrink-wrapping.ll

diff --git a/test/CodeGen/X86/x86-shrink-wrapping.ll b/test/CodeGen/X86/x86-shrink-wrapping.ll
index b5a3174f10e5dc1a4365dfb74131c774deac9b6d..609e2cc1158c98d7ce214122e8102ec8e8f888c6 100644 (file)
--- a/test/CodeGen/X86/x86-shrink-wrapping.ll
+++ b/test/CodeGen/X86/x86-shrink-wrapping.ll
@@ -923,3 +923,64 @@ exit:
 }
 
 attributes #3 = { nounwind }
+
+@irreducibleCFGa = common global i32 0, align 4
+@irreducibleCFGf = common global i8 0, align 1
+@irreducibleCFGb = common global i32 0, align 4
+
+; Check that we do not run shrink-wrapping on irreducible CFGs until
+; it is actually supported.
+; At the moment, on those CFGs the loop information may be incorrect
+; and since we use that information to do the placement, we may end up
+; inserting the prologue/epilogue at incorrect places.
+; PR25988.
+;
+; CHECK-LABEL: irreducibleCFG:
+; CHECK: %entry
+; Make sure the prologue happens in the entry block.
+; CHECK-NEXT: pushq
+; ...
+; Make sure the epilogue happens in the exit block.
+; CHECK-NOT: popq
+; CHECK: popq
+; CHECK-NEXT: popq
+; CHECK-NEXT: retq
+define i32 @irreducibleCFG() #4 {
+entry:
+  %i0 = load i32, i32* @irreducibleCFGa, align 4
+  %.pr = load i8, i8* @irreducibleCFGf, align 1
+  %bool = icmp eq i8 %.pr, 0
+  br i1 %bool, label %split, label %preheader
+
+preheader:
+  br label %preheader
+
+split:
+  %i1 = load i32, i32* @irreducibleCFGb, align 4
+  %tobool1.i = icmp ne i32 %i1, 0
+  br i1 %tobool1.i, label %for.body4.i, label %for.cond8.i.preheader
+
+for.body4.i:
+  %call.i = tail call i32 (...) @something(i32 %i0)
+  br label %for.cond8
+
+for.cond8:
+  %p1 = phi i32 [ %inc18.i, %for.inc ], [ 0, %for.body4.i ]
+  %.pr1.pr = load i32, i32* @irreducibleCFGb, align 4
+  br label %for.cond8.i.preheader
+
+for.cond8.i.preheader:
+  %.pr1 = phi i32 [ %.pr1.pr, %for.cond8 ], [ %i1, %split ]
+  %p13 = phi i32 [ %p1, %for.cond8 ], [ 0, %split ]
+  br label %for.inc
+
+fn1.exit:
+  ret i32 0
+
+for.inc:
+  %inc18.i = add nuw nsw i32 %p13, 1
+  %cmp = icmp slt i32 %inc18.i, 7
+  br i1 %cmp, label %for.cond8, label %fn1.exit
+}
+
+attributes #4 = { "no-frame-pointer-elim"="true" }