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