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| ; RUN: opt < %s -simplifycfg -S | FileCheck %s
; Skip simplifying unconditional branches from empty blocks in simplifyCFG,
; when it can destroy canonical loop structure.
; void foo();
; bool test(int a, int b, int *c) {
; bool changed = false;
; for (unsigned int i = 2; i--;) {
; int r = a | b;
; if ( r != c[i]) {
; c[i] = r;
; foo();
; changed = true;
; }
; }
; return changed;
; }
; CHECK-LABEL: @test(
; CHECK: for.cond:
; CHECK-NEXT: %i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
; CHECK: for.body:
; CHECK: br i1 %cmp, label %if.end, label %if.then
; CHECK-NOT: br i1 %cmp, label %for.cond, label %if.then
; CHECK: if.then:
; CHECK: br label %if.end
; CHECK-NOT: br label %for.cond
; CHECK: if.end:
; CHECK br label %for.cond
define i1 @test(i32 %a, i32 %b, i32* %c) {
entry:
br label %for.cond
for.cond: ; preds = %if.end, %entry
%i.0 = phi i32 [ 2, %entry ], [ %dec, %if.end ]
%changed.0.off0 = phi i1 [ false, %entry ], [ %changed.1.off0, %if.end ]
%dec = add nsw i32 %i.0, -1
%tobool = icmp eq i32 %i.0, 0
br i1 %tobool, label %for.cond.cleanup, label %for.body
for.cond.cleanup: ; preds = %for.cond
%changed.0.off0.lcssa = phi i1 [ %changed.0.off0, %for.cond ]
ret i1 %changed.0.off0.lcssa
for.body: ; preds = %for.cond
%or = or i32 %a, %b
%idxprom = sext i32 %dec to i64
%arrayidx = getelementptr inbounds i32, i32* %c, i64 %idxprom
%0 = load i32, i32* %arrayidx, align 4
%cmp = icmp eq i32 %or, %0
br i1 %cmp, label %if.end, label %if.then
if.then: ; preds = %for.body
store i32 %or, i32* %arrayidx, align 4
call void @foo()
br label %if.end
if.end: ; preds = %for.body, %if.then
%changed.1.off0 = phi i1 [ true, %if.then ], [ %changed.0.off0, %for.body ]
br label %for.cond
}
declare void @foo()
|