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