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156 lines
4.5 KiB
156 lines
4.5 KiB
; RUN: opt -codegenprepare -S < %s | FileCheck %s
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target triple = "x86_64-unknown-unknown"
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; Nothing to sink and convert here.
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define i32 @no_sink(double %a, double* %b, i32 %x, i32 %y) {
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entry:
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%load = load double, double* %b, align 8
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%cmp = fcmp olt double %load, %a
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%sel = select i1 %cmp, i32 %x, i32 %y
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ret i32 %sel
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; CHECK-LABEL: @no_sink(
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; CHECK: %load = load double, double* %b, align 8
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; CHECK: %cmp = fcmp olt double %load, %a
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; CHECK: %sel = select i1 %cmp, i32 %x, i32 %y
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; CHECK: ret i32 %sel
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}
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; An 'fdiv' is expensive, so sink it rather than speculatively execute it.
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define float @fdiv_true_sink(float %a, float %b) {
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entry:
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%div = fdiv float %a, %b
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%cmp = fcmp ogt float %a, 1.0
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%sel = select i1 %cmp, float %div, float 2.0
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ret float %sel
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; CHECK-LABEL: @fdiv_true_sink(
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; CHECK: %cmp = fcmp ogt float %a, 1.0
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; CHECK: br i1 %cmp, label %select.true.sink, label %select.end
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; CHECK: select.true.sink:
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; CHECK: %div = fdiv float %a, %b
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; CHECK: br label %select.end
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; CHECK: select.end:
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; CHECK: %sel = phi float [ %div, %select.true.sink ], [ 2.000000e+00, %entry ]
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; CHECK: ret float %sel
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}
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define float @fdiv_false_sink(float %a, float %b) {
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entry:
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%div = fdiv float %a, %b
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%cmp = fcmp ogt float %a, 3.0
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%sel = select i1 %cmp, float 4.0, float %div
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ret float %sel
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; CHECK-LABEL: @fdiv_false_sink(
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; CHECK: %cmp = fcmp ogt float %a, 3.0
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; CHECK: br i1 %cmp, label %select.end, label %select.false.sink
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; CHECK: select.false.sink:
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; CHECK: %div = fdiv float %a, %b
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; CHECK: br label %select.end
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; CHECK: select.end:
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; CHECK: %sel = phi float [ 4.000000e+00, %entry ], [ %div, %select.false.sink ]
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; CHECK: ret float %sel
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}
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define float @fdiv_both_sink(float %a, float %b) {
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entry:
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%div1 = fdiv float %a, %b
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%div2 = fdiv float %b, %a
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%cmp = fcmp ogt float %a, 5.0
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%sel = select i1 %cmp, float %div1, float %div2
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ret float %sel
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; CHECK-LABEL: @fdiv_both_sink(
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; CHECK: %cmp = fcmp ogt float %a, 5.0
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; CHECK: br i1 %cmp, label %select.true.sink, label %select.false.sink
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; CHECK: select.true.sink:
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; CHECK: %div1 = fdiv float %a, %b
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; CHECK: br label %select.end
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; CHECK: select.false.sink:
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; CHECK: %div2 = fdiv float %b, %a
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; CHECK: br label %select.end
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; CHECK: select.end:
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; CHECK: %sel = phi float [ %div1, %select.true.sink ], [ %div2, %select.false.sink ]
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; CHECK: ret float %sel
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}
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; But if the select is marked unpredictable, then don't turn it into a branch.
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define float @unpredictable_select(float %a, float %b) {
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; CHECK-LABEL: @unpredictable_select(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[DIV:%.*]] = fdiv float %a, %b
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; CHECK-NEXT: [[CMP:%.*]] = fcmp ogt float %a, 1.000000e+00
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; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], float [[DIV]], float 2.000000e+00, !unpredictable !0
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; CHECK-NEXT: ret float [[SEL]]
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;
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entry:
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%div = fdiv float %a, %b
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%cmp = fcmp ogt float %a, 1.0
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%sel = select i1 %cmp, float %div, float 2.0, !unpredictable !0
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ret float %sel
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}
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!0 = !{}
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; An 'fadd' is not too expensive, so it's ok to speculate.
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define float @fadd_no_sink(float %a, float %b) {
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%add = fadd float %a, %b
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%cmp = fcmp ogt float 6.0, %a
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%sel = select i1 %cmp, float %add, float 7.0
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ret float %sel
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; CHECK-LABEL: @fadd_no_sink(
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; CHECK: %sel = select i1 %cmp, float %add, float 7.0
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}
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; Possible enhancement: sinkability is only calculated with the direct
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; operand of the select, so we don't try to sink this. The fdiv cost is not
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; taken into account.
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define float @fdiv_no_sink(float %a, float %b) {
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entry:
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%div = fdiv float %a, %b
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%add = fadd float %div, %b
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%cmp = fcmp ogt float %a, 1.0
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%sel = select i1 %cmp, float %add, float 8.0
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ret float %sel
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; CHECK-LABEL: @fdiv_no_sink(
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; CHECK: %sel = select i1 %cmp, float %add, float 8.0
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}
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; Do not transform the CFG if the select operands may have side effects.
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declare i64* @bar(i32, i32, i32)
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declare i64* @baz(i32, i32, i32)
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define i64* @calls_no_sink(i32 %in) {
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%call1 = call i64* @bar(i32 1, i32 2, i32 3)
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%call2 = call i64* @baz(i32 1, i32 2, i32 3)
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%tobool = icmp ne i32 %in, 0
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%sel = select i1 %tobool, i64* %call1, i64* %call2
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ret i64* %sel
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; CHECK-LABEL: @calls_no_sink(
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; CHECK: %sel = select i1 %tobool, i64* %call1, i64* %call2
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}
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define i32 @sdiv_no_sink(i32 %a, i32 %b) {
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%div1 = sdiv i32 %a, %b
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%div2 = sdiv i32 %b, %a
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%cmp = icmp sgt i32 %a, 5
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%sel = select i1 %cmp, i32 %div1, i32 %div2
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ret i32 %sel
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; CHECK-LABEL: @sdiv_no_sink(
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; CHECK: %sel = select i1 %cmp, i32 %div1, i32 %div2
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}
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