1 ; RUN: opt < %s -simplifycfg -S | FileCheck %s
3 ; Skip simplifying unconditional branches from empty blocks in simplifyCFG,
4 ; when it can destroy canonical loop structure.
7 ; bool test(int a, int b, int *c) {
8 ; bool changed = false;
9 ; for (unsigned int i = 2; i--;) {
22 ; CHECK-NEXT: %i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
24 ; CHECK: br i1 %cmp, label %if.end, label %if.then
25 ; CHECK-NOT: br i1 %cmp, label %for.cond, label %if.then
27 ; CHECK: br label %if.end
28 ; CHECK-NOT: br label %for.cond
30 ; CHECK br label %for.cond
31 define i1 @test(i32 %a, i32 %b, i32* %c) {
35 for.cond: ; preds = %if.end, %entry
36 %i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
37 %changed.0.off0 = phi i1 [ false, %entry ], [ %changed.1.off0, %if.end ]
38 %dec = add nsw i32 %i.0, -1
39 %tobool = icmp eq i32 %i.0, 0
40 br i1 %tobool, label %for.cond.cleanup, label %for.body
42 for.cond.cleanup: ; preds = %for.cond
43 %changed.0.off0.lcssa = phi i1 [ %changed.0.off0, %for.cond ]
44 ret i1 %changed.0.off0.lcssa
46 for.body: ; preds = %for.cond
48 %idxprom = sext i32 %dec to i64
49 %arrayidx = getelementptr inbounds i32, i32* %c, i64 %idxprom
50 %0 = load i32, i32* %arrayidx, align 4
51 %cmp = icmp eq i32 %or, %0
52 br i1 %cmp, label %if.end, label %if.then
54 if.then: ; preds = %for.body
55 store i32 %or, i32* %arrayidx, align 4
59 if.end: ; preds = %for.body, %if.then
60 %changed.1.off0 = phi i1 [ true, %if.then ], [ %changed.0.off0, %for.body ]