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