508 lines
13 KiB
LLVM
508 lines
13 KiB
LLVM
; Specifically exercise the cost modeling for non-trivial loop unswitching.
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;
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; RUN: opt -passes='loop(simple-loop-unswitch<nontrivial>),verify<loops>' -unswitch-threshold=5 -S < %s | FileCheck %s
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; RUN: opt -passes='loop-mssa(simple-loop-unswitch<nontrivial>),verify<loops>' -unswitch-threshold=5 -S < %s | FileCheck %s
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; RUN: opt -simple-loop-unswitch -enable-nontrivial-unswitch -unswitch-threshold=5 -verify-memoryssa -S < %s | FileCheck %s
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declare void @a()
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declare void @b()
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declare void @x()
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; First establish enough code size in the duplicated 'loop_begin' block to
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; suppress unswitching.
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define void @test_no_unswitch(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_no_unswitch(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label %loop_begin
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;
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; We shouldn't have unswitched into any other block either.
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; CHECK-NOT: br i1 %cond
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loop_begin:
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call void @x()
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call void @x()
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call void @x()
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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call void @a()
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br label %loop_latch
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loop_b:
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call void @b()
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br label %loop_latch
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loop_latch:
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%v = load i1, i1* %ptr
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br i1 %v, label %loop_begin, label %loop_exit
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loop_exit:
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ret void
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}
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; Now check that the smaller formulation of 'loop_begin' does in fact unswitch
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; with our low threshold.
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define void @test_unswitch(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_unswitch(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[FROZEN:%.+]] = freeze i1 %cond
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; CHECK-NEXT: br i1 [[FROZEN]], label %entry.split.us, label %entry.split
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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call void @a()
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br label %loop_latch
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; The 'loop_a' unswitched loop.
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;
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; CHECK: entry.split.us:
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; CHECK-NEXT: br label %loop_begin.us
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;
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; CHECK: loop_begin.us:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_a.us
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;
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; CHECK: loop_a.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_latch.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us
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;
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; CHECK: loop_exit.split.us:
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; CHECK-NEXT: br label %loop_exit
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loop_b:
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call void @b()
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br label %loop_latch
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; The 'loop_b' unswitched loop.
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;
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; CHECK: entry.split:
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; CHECK-NEXT: br label %loop_begin
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;
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_b
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;
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; CHECK: loop_b:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: br label %loop_latch
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;
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; CHECK: loop_latch:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin, label %loop_exit.split
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;
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; CHECK: loop_exit.split:
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; CHECK-NEXT: br label %loop_exit
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loop_latch:
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%v = load i1, i1* %ptr
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br i1 %v, label %loop_begin, label %loop_exit
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loop_exit:
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ret void
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; CHECK: loop_exit:
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; CHECK-NEXT: ret void
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}
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; Check that even with large amounts of code on either side of the unswitched
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; branch, if that code would be kept in only one of the unswitched clones it
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; doesn't contribute to the cost.
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define void @test_unswitch_non_dup_code(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_unswitch_non_dup_code(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[FROZEN:%.+]] = freeze i1 %cond
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; CHECK-NEXT: br i1 [[FROZEN]], label %entry.split.us, label %entry.split
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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call void @a()
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call void @a()
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call void @a()
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call void @a()
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br label %loop_latch
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; The 'loop_a' unswitched loop.
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;
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; CHECK: entry.split.us:
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; CHECK-NEXT: br label %loop_begin.us
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;
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; CHECK: loop_begin.us:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_a.us
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;
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; CHECK: loop_a.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_latch.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us
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;
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; CHECK: loop_exit.split.us:
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; CHECK-NEXT: br label %loop_exit
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loop_b:
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call void @b()
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call void @b()
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call void @b()
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call void @b()
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br label %loop_latch
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; The 'loop_b' unswitched loop.
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;
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; CHECK: entry.split:
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; CHECK-NEXT: br label %loop_begin
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;
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_b
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;
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; CHECK: loop_b:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: br label %loop_latch
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;
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; CHECK: loop_latch:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin, label %loop_exit.split
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;
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; CHECK: loop_exit.split:
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; CHECK-NEXT: br label %loop_exit
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loop_latch:
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%v = load i1, i1* %ptr
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br i1 %v, label %loop_begin, label %loop_exit
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loop_exit:
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ret void
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; CHECK: loop_exit:
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; CHECK-NEXT: ret void
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}
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; Much like with non-duplicated code directly in the successor, we also won't
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; duplicate even interesting CFGs.
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define void @test_unswitch_non_dup_code_in_cfg(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_unswitch_non_dup_code_in_cfg(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[FROZEN:%.+]] = freeze i1 %cond
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; CHECK-NEXT: br i1 [[FROZEN]], label %entry.split.us, label %entry.split
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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%v1 = load i1, i1* %ptr
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br i1 %v1, label %loop_a_a, label %loop_a_b
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loop_a_a:
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call void @a()
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br label %loop_latch
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loop_a_b:
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call void @a()
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br label %loop_latch
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; The 'loop_a' unswitched loop.
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;
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; CHECK: entry.split.us:
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; CHECK-NEXT: br label %loop_begin.us
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;
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; CHECK: loop_begin.us:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_a.us
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;
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; CHECK: loop_a.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_a_a.us, label %loop_a_b.us
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;
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; CHECK: loop_a_b.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_a_a.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_latch.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us
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;
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; CHECK: loop_exit.split.us:
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; CHECK-NEXT: br label %loop_exit
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loop_b:
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%v2 = load i1, i1* %ptr
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br i1 %v2, label %loop_b_a, label %loop_b_b
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loop_b_a:
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call void @b()
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br label %loop_latch
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loop_b_b:
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call void @b()
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br label %loop_latch
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; The 'loop_b' unswitched loop.
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;
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; CHECK: entry.split:
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; CHECK-NEXT: br label %loop_begin
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;
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_b
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;
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; CHECK: loop_b:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_b_a, label %loop_b_b
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;
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; CHECK: loop_b_a:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: br label %loop_latch
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;
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; CHECK: loop_b_b:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: br label %loop_latch
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;
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; CHECK: loop_latch:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin, label %loop_exit.split
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;
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; CHECK: loop_exit.split:
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; CHECK-NEXT: br label %loop_exit
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loop_latch:
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%v3 = load i1, i1* %ptr
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br i1 %v3, label %loop_begin, label %loop_exit
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loop_exit:
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ret void
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; CHECK: loop_exit:
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; CHECK-NEXT: ret void
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}
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; Check that even if there is *some* non-duplicated code on one side of an
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; unswitch, we don't count any other code in the loop that will in fact have to
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; be duplicated.
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define void @test_no_unswitch_non_dup_code(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_no_unswitch_non_dup_code(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label %loop_begin
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;
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; We shouldn't have unswitched into any other block either.
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; CHECK-NOT: br i1 %cond
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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%v1 = load i1, i1* %ptr
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br i1 %v1, label %loop_a_a, label %loop_a_b
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loop_a_a:
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call void @a()
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br label %loop_latch
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loop_a_b:
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call void @a()
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br label %loop_latch
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loop_b:
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%v2 = load i1, i1* %ptr
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br i1 %v2, label %loop_b_a, label %loop_b_b
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loop_b_a:
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call void @b()
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br label %loop_latch
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loop_b_b:
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call void @b()
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br label %loop_latch
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loop_latch:
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call void @x()
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call void @x()
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%v = load i1, i1* %ptr
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br i1 %v, label %loop_begin, label %loop_exit
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loop_exit:
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ret void
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}
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; Check that we still unswitch when the exit block contains lots of code, even
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; though we do clone the exit block as part of unswitching. This should work
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; because we should split the exit block before anything inside it.
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define void @test_unswitch_large_exit(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_unswitch_large_exit(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[FROZEN:%.+]] = freeze i1 %cond
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; CHECK-NEXT: br i1 [[FROZEN]], label %entry.split.us, label %entry.split
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b
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loop_a:
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call void @a()
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br label %loop_latch
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; The 'loop_a' unswitched loop.
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;
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; CHECK: entry.split.us:
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; CHECK-NEXT: br label %loop_begin.us
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;
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; CHECK: loop_begin.us:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_a.us
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;
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; CHECK: loop_a.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_latch.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us
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;
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; CHECK: loop_exit.split.us:
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; CHECK-NEXT: br label %loop_exit
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loop_b:
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call void @b()
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br label %loop_latch
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; The 'loop_b' unswitched loop.
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;
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; CHECK: entry.split:
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; CHECK-NEXT: br label %loop_begin
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;
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_b
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;
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; CHECK: loop_b:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: br label %loop_latch
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;
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; CHECK: loop_latch:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin, label %loop_exit.split
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;
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; CHECK: loop_exit.split:
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; CHECK-NEXT: br label %loop_exit
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loop_latch:
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%v = load i1, i1* %ptr
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br i1 %v, label %loop_begin, label %loop_exit
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loop_exit:
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call void @x()
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call void @x()
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call void @x()
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call void @x()
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ret void
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; CHECK: loop_exit:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: ret void
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}
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; Check that we handle a dedicated exit edge unswitch which is still
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; non-trivial and has lots of code in the exit.
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define void @test_unswitch_dedicated_exiting(i1* %ptr, i1 %cond) {
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; CHECK-LABEL: @test_unswitch_dedicated_exiting(
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entry:
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br label %loop_begin
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[FROZEN:%.+]] = freeze i1 %cond
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; CHECK-NEXT: br i1 [[FROZEN]], label %entry.split.us, label %entry.split
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loop_begin:
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call void @x()
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br i1 %cond, label %loop_a, label %loop_b_exit
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loop_a:
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call void @a()
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br label %loop_latch
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; The 'loop_a' unswitched loop.
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;
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; CHECK: entry.split.us:
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; CHECK-NEXT: br label %loop_begin.us
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;
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; CHECK: loop_begin.us:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_a.us
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;
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; CHECK: loop_a.us:
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; CHECK-NEXT: call void @a()
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; CHECK-NEXT: br label %loop_latch.us
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;
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; CHECK: loop_latch.us:
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; CHECK-NEXT: %[[V:.*]] = load i1, i1* %ptr
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; CHECK-NEXT: br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us
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;
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; CHECK: loop_exit.split.us:
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; CHECK-NEXT: br label %loop_exit
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loop_b_exit:
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call void @b()
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call void @b()
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call void @b()
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call void @b()
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ret void
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; The 'loop_b_exit' unswitched exit path.
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;
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; CHECK: entry.split:
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; CHECK-NEXT: br label %loop_begin
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;
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; CHECK: loop_begin:
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; CHECK-NEXT: call void @x()
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; CHECK-NEXT: br label %loop_b_exit
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;
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; CHECK: loop_b_exit:
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: call void @b()
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; CHECK-NEXT: ret void
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loop_latch:
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%v = load i1, i1* %ptr
|
|
br i1 %v, label %loop_begin, label %loop_exit
|
|
|
|
loop_exit:
|
|
ret void
|
|
; CHECK: loop_exit:
|
|
; CHECK-NEXT: ret void
|
|
}
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