Implement PR1786 by iterating between dead cycle elimination
and simplifycfg in the rare cases when it is needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44044 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Transforms/SimplifyCFG/iterative-simplify.ll b/test/Transforms/SimplifyCFG/iterative-simplify.ll
new file mode 100644
index 0000000..9081b01
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/iterative-simplify.ll
@@ -0,0 +1,100 @@
+; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | not grep bb17
+; PR1786
+
+define i32 @main() {
+entry:
+ %retval = alloca i32, align 4 ; <i32*> [#uses=1]
+ %i = alloca i32, align 4 ; <i32*> [#uses=7]
+ %z = alloca i32, align 4 ; <i32*> [#uses=4]
+ %z16 = alloca i32, align 4 ; <i32*> [#uses=4]
+ %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
+ store i32 0, i32* %i
+ %toBool = icmp ne i8 1, 0 ; <i1> [#uses=1]
+ br i1 %toBool, label %cond_true, label %cond_false
+
+cond_true: ; preds = %entry
+ store i32 0, i32* %z
+ br label %bb
+
+bb: ; preds = %cond_next, %cond_true
+ %tmp = load i32* %z ; <i32> [#uses=1]
+ %tmp1 = sub i32 %tmp, 16384 ; <i32> [#uses=1]
+ store i32 %tmp1, i32* %z
+ %tmp2 = load i32* %i ; <i32> [#uses=1]
+ %tmp3 = add i32 %tmp2, 1 ; <i32> [#uses=1]
+ store i32 %tmp3, i32* %i
+ %tmp4 = load i32* %i ; <i32> [#uses=1]
+ %tmp5 = icmp sgt i32 %tmp4, 262144 ; <i1> [#uses=1]
+ %tmp56 = zext i1 %tmp5 to i8 ; <i8> [#uses=1]
+ %toBool7 = icmp ne i8 %tmp56, 0 ; <i1> [#uses=1]
+ br i1 %toBool7, label %cond_true8, label %cond_next
+
+cond_true8: ; preds = %bb
+ call void @abort( )
+ unreachable
+
+cond_next: ; preds = %bb
+ %tmp9 = load i32* %z ; <i32> [#uses=1]
+ %tmp10 = icmp ne i32 %tmp9, 0 ; <i1> [#uses=1]
+ %tmp1011 = zext i1 %tmp10 to i8 ; <i8> [#uses=1]
+ %toBool12 = icmp ne i8 %tmp1011, 0 ; <i1> [#uses=1]
+ br i1 %toBool12, label %bb, label %bb13
+
+bb13: ; preds = %cond_next
+ call void @exit( i32 0 )
+ unreachable
+
+cond_false: ; preds = %entry
+ %toBool14 = icmp ne i8 1, 0 ; <i1> [#uses=1]
+ br i1 %toBool14, label %cond_true15, label %cond_false33
+
+cond_true15: ; preds = %cond_false
+ store i32 0, i32* %z16
+ br label %bb17
+
+bb17: ; preds = %cond_next27, %cond_true15
+ %tmp18 = load i32* %z16 ; <i32> [#uses=1]
+ %tmp19 = sub i32 %tmp18, 16384 ; <i32> [#uses=1]
+ store i32 %tmp19, i32* %z16
+ %tmp20 = load i32* %i ; <i32> [#uses=1]
+ %tmp21 = add i32 %tmp20, 1 ; <i32> [#uses=1]
+ store i32 %tmp21, i32* %i
+ %tmp22 = load i32* %i ; <i32> [#uses=1]
+ %tmp23 = icmp sgt i32 %tmp22, 262144 ; <i1> [#uses=1]
+ %tmp2324 = zext i1 %tmp23 to i8 ; <i8> [#uses=1]
+ %toBool25 = icmp ne i8 %tmp2324, 0 ; <i1> [#uses=1]
+ br i1 %toBool25, label %cond_true26, label %cond_next27
+
+cond_true26: ; preds = %bb17
+ call void @abort( )
+ unreachable
+
+cond_next27: ; preds = %bb17
+ %tmp28 = load i32* %z16 ; <i32> [#uses=1]
+ %tmp29 = icmp ne i32 %tmp28, 0 ; <i1> [#uses=1]
+ %tmp2930 = zext i1 %tmp29 to i8 ; <i8> [#uses=1]
+ %toBool31 = icmp ne i8 %tmp2930, 0 ; <i1> [#uses=1]
+ br i1 %toBool31, label %bb17, label %bb32
+
+bb32: ; preds = %cond_next27
+ call void @exit( i32 0 )
+ unreachable
+
+cond_false33: ; preds = %cond_false
+ call void @exit( i32 0 )
+ unreachable
+
+cond_next34: ; No predecessors!
+ br label %cond_next35
+
+cond_next35: ; preds = %cond_next34
+ br label %return
+
+return: ; preds = %cond_next35
+ %retval36 = load i32* %retval ; <i32> [#uses=1]
+ ret i32 %retval36
+}
+
+declare void @abort()
+
+declare void @exit(i32)