1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 03:33:20 +01:00
llvm-mirror/test/Transforms/SCCP/switch.ll
Nikita Popov 6a6a8d731b [SCCP] Remove dead switch cases based on range information
Determine whether switch edges are feasible based on range information,
and remove non-feasible edges lateron.

This does not try to determine whether the default edge is dead,
as we'd have to determine that the range is fully covered by the
cases for that.

Another limitation here is that we don't remove dead cases that
have the same successor as a live case. I'm not handling this
because I wanted to keep the edge removal based on feasible edges
only, rather than inspecting ranges again there -- this does not
seem like a particularly useful case to handle.

Differential Revision: https://reviews.llvm.org/D84270
2020-07-30 21:21:08 +02:00

255 lines
6.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -ipsccp < %s | FileCheck %s
; Make sure we always consider the default edge executable for a switch
; with no cases.
declare void @foo()
define void @test1() {
; CHECK-LABEL: @test1(
; CHECK-NEXT: switch i32 undef, label [[D:%.*]] [
; CHECK-NEXT: ]
; CHECK: d:
; CHECK-NEXT: call void @foo()
; CHECK-NEXT: ret void
;
switch i32 undef, label %d []
d:
call void @foo()
ret void
}
define i32 @test_duplicate_successors_phi(i1 %c, i32 %x) {
; CHECK-LABEL: @test_duplicate_successors_phi(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C:%.*]], label [[SWITCH:%.*]], label [[END:%.*]]
; CHECK: switch:
; CHECK-NEXT: br label [[SWITCH_DEFAULT:%.*]]
; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1
; CHECK: end:
; CHECK-NEXT: ret i32 [[X:%.*]]
;
entry:
br i1 %c, label %switch, label %end
switch:
switch i32 -1, label %switch.default [
i32 0, label %end
i32 1, label %end
]
switch.default:
ret i32 -1
end:
%phi = phi i32 [ %x, %entry ], [ 1, %switch ], [ 1, %switch ]
ret i32 %phi
}
define i32 @test_duplicate_successors_phi_2(i1 %c, i32 %x) {
; CHECK-LABEL: @test_duplicate_successors_phi_2(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C:%.*]], label [[SWITCH:%.*]], label [[END:%.*]]
; CHECK: switch:
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ 1, [[SWITCH]] ]
; CHECK-NEXT: ret i32 [[PHI]]
;
entry:
br i1 %c, label %switch, label %end
switch:
switch i32 0, label %switch.default [
i32 0, label %end
i32 1, label %end
]
switch.default:
ret i32 -1
end:
%phi = phi i32 [ %x, %entry ], [ 1, %switch ], [ 1, %switch ]
ret i32 %phi
}
define i32 @test_duplicate_successors_phi_3(i1 %c1, i32* %p, i32 %y) {
; CHECK-LABEL: @test_duplicate_successors_phi_3(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C1:%.*]], label [[SWITCH:%.*]], label [[SWITCH_1:%.*]]
; CHECK: switch:
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4, !range !0
; CHECK-NEXT: switch i32 [[X]], label [[SWITCH_DEFAULT:%.*]] [
; CHECK-NEXT: i32 0, label [[SWITCH_DEFAULT]]
; CHECK-NEXT: i32 1, label [[SWITCH_0:%.*]]
; CHECK-NEXT: i32 2, label [[SWITCH_0]]
; CHECK-NEXT: ]
; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1
; CHECK: switch.0:
; CHECK-NEXT: ret i32 0
; CHECK: switch.1:
; CHECK-NEXT: ret i32 [[Y:%.*]]
;
entry:
br i1 %c1, label %switch, label %switch.1
switch:
%x = load i32, i32* %p, !range !{i32 0, i32 3}
switch i32 %x, label %switch.default [
i32 0, label %switch.default
i32 1, label %switch.0
i32 2, label %switch.0
i32 3, label %switch.1
i32 4, label %switch.1
]
switch.default:
ret i32 -1
switch.0:
ret i32 0
switch.1:
%phi = phi i32 [ %y, %entry ], [ 0, %switch ], [ 0, %switch ]
ret i32 %phi
}
; TODO: Determine that the default destination is dead.
define i32 @test_local_range(i32* %p) {
; CHECK-LABEL: @test_local_range(
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4, !range !0
; CHECK-NEXT: switch i32 [[X]], label [[SWITCH_DEFAULT:%.*]] [
; CHECK-NEXT: i32 0, label [[SWITCH_0:%.*]]
; CHECK-NEXT: i32 1, label [[SWITCH_1:%.*]]
; CHECK-NEXT: i32 2, label [[SWITCH_2:%.*]]
; CHECK-NEXT: ]
; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1
; CHECK: switch.0:
; CHECK-NEXT: ret i32 0
; CHECK: switch.1:
; CHECK-NEXT: ret i32 1
; CHECK: switch.2:
; CHECK-NEXT: ret i32 2
;
%x = load i32, i32* %p, !range !{i32 0, i32 3}
switch i32 %x, label %switch.default [
i32 0, label %switch.0
i32 1, label %switch.1
i32 2, label %switch.2
i32 3, label %switch.3
]
switch.default:
ret i32 -1
switch.0:
ret i32 0
switch.1:
ret i32 1
switch.2:
ret i32 2
switch.3:
ret i32 3
}
; TODO: Determine that case i3 is dead, even though the edge is shared?
define i32 @test_duplicate_successors(i32* %p) {
; CHECK-LABEL: @test_duplicate_successors(
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4, !range !0
; CHECK-NEXT: switch i32 [[X]], label [[SWITCH_DEFAULT:%.*]] [
; CHECK-NEXT: i32 0, label [[SWITCH_0:%.*]]
; CHECK-NEXT: i32 1, label [[SWITCH_0]]
; CHECK-NEXT: i32 2, label [[SWITCH_1:%.*]]
; CHECK-NEXT: i32 3, label [[SWITCH_1]]
; CHECK-NEXT: ]
; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1
; CHECK: switch.0:
; CHECK-NEXT: ret i32 0
; CHECK: switch.1:
; CHECK-NEXT: ret i32 1
;
%x = load i32, i32* %p, !range !{i32 0, i32 3}
switch i32 %x, label %switch.default [
i32 0, label %switch.0
i32 1, label %switch.0
i32 2, label %switch.1
i32 3, label %switch.1
i32 4, label %switch.2
i32 5, label %switch.2
]
switch.default:
ret i32 -1
switch.0:
ret i32 0
switch.1:
ret i32 1
switch.2:
ret i32 2
}
; Case i32 2 is dead as well, but this cannot be determined based on
; range information.
define internal i32 @test_ip_range(i32 %x) {
; CHECK-LABEL: @test_ip_range(
; CHECK-NEXT: switch i32 [[X:%.*]], label [[SWITCH_DEFAULT:%.*]] [
; CHECK-NEXT: i32 3, label [[SWITCH_3:%.*]]
; CHECK-NEXT: i32 1, label [[SWITCH_1:%.*]]
; CHECK-NEXT: i32 2, label [[SWITCH_2:%.*]]
; CHECK-NEXT: ], !prof !1
; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1
; CHECK: switch.1:
; CHECK-NEXT: ret i32 1
; CHECK: switch.2:
; CHECK-NEXT: ret i32 2
; CHECK: switch.3:
; CHECK-NEXT: ret i32 3
;
switch i32 %x, label %switch.default [
i32 0, label %switch.0
i32 1, label %switch.1
i32 2, label %switch.2
i32 3, label %switch.3
], !prof !{!"branch_weights", i32 1, i32 2, i32 3, i32 4, i32 5}
switch.default:
ret i32 -1
switch.0:
ret i32 0
switch.1:
ret i32 1
switch.2:
ret i32 2
switch.3:
ret i32 3
}
define void @call_test_ip_range() {
; CHECK-LABEL: @call_test_ip_range(
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @test_ip_range(i32 1)
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @test_ip_range(i32 3)
; CHECK-NEXT: ret void
;
call i32 @test_ip_range(i32 1)
call i32 @test_ip_range(i32 3)
ret void
}
declare void @llvm.assume(i1)
; CHECK: !1 = !{!"branch_weights", i32 1, i32 5, i32 3, i32 4}