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; RUN: opt -S -deadargelim %s | FileCheck %s
; Case 0: the basic example: an entire aggregate use is returned, but it's
; actually only used in ways we can eliminate. We gain benefit from analysing
; the "use" and applying its results to all sub-values.
; CHECK-LABEL: define internal void @agguse_dead()
define internal { i32, i32 } @agguse_dead() {
ret { i32, i32 } { i32 0, i32 1 }
}
define internal { i32, i32 } @test_agguse_dead() {
%val = call { i32, i32 } @agguse_dead()
ret { i32, i32 } %val
}
; Case 1: an opaque use of the aggregate exists (in this case dead). Otherwise
; only one value is used, so function can be simplified.
; CHECK-LABEL: define internal i32 @rets_independent_if_agguse_dead()
; CHECK: [[RET:%.*]] = extractvalue { i32, i32 } { i32 0, i32 1 }, 1
; CHECK: ret i32 [[RET]]
define internal { i32, i32 } @rets_independent_if_agguse_dead() {
ret { i32, i32 } { i32 0, i32 1 }
}
define internal { i32, i32 } @test_rets_independent_if_agguse_dead(i1 %tst) {
%val = call { i32, i32 } @rets_independent_if_agguse_dead()
br i1 %tst, label %use_1, label %use_aggregate
use_1:
; This use can be classified as applying only to ret 1.
%val0 = extractvalue { i32, i32 } %val, 1
call void @callee(i32 %val0)
ret { i32, i32 } undef
use_aggregate:
; This use is assumed to apply to both 0 and 1.
ret { i32, i32 } %val
}
; Case 2: an opaque use of the aggregate exists (in this case *live*). Other
; uses shouldn't matter.
; CHECK-LABEL: define internal { i32, i32 } @rets_live_agguse()
; CHECK: ret { i32, i32 } { i32 0, i32 1 }
define internal { i32, i32 } @rets_live_agguse() {
ret { i32, i32} { i32 0, i32 1 }
}
define { i32, i32 } @test_rets_live_aggues(i1 %tst) {
%val = call { i32, i32 } @rets_live_agguse()
br i1 %tst, label %use_1, label %use_aggregate
use_1:
; This use can be classified as applying only to ret 1.
%val0 = extractvalue { i32, i32 } %val, 1
call void @callee(i32 %val0)
ret { i32, i32 } undef
use_aggregate:
; This use is assumed to apply to both 0 and 1.
ret { i32, i32 } %val
}
declare void @callee(i32)
; Case 3: the insertvalue meant %in was live if ret-slot-1 was, but we were only
; tracking multiple ret-slots for struct types. So %in was eliminated
; incorrectly.
; CHECK-LABEL: define internal [2 x i32] @array_rets_have_multiple_slots(i32 %in)
define internal [2 x i32] @array_rets_have_multiple_slots(i32 %in) {
%ret = insertvalue [2 x i32] undef, i32 %in, 1
ret [2 x i32] %ret
}
define [2 x i32] @test_array_rets_have_multiple_slots() {
%res = call [2 x i32] @array_rets_have_multiple_slots(i32 42)
ret [2 x i32] %res
}
; Case 4: we can remove some retvals from the array. It's nice to produce an
; array again having done so (rather than converting it to a struct).
; CHECK-LABEL: define internal [2 x i32] @can_shrink_arrays()
; CHECK: [[VAL0:%.*]] = extractvalue [3 x i32] [i32 42, i32 43, i32 44], 0
; CHECK: [[RESTMP:%.*]] = insertvalue [2 x i32] undef, i32 [[VAL0]], 0
; CHECK: [[VAL2:%.*]] = extractvalue [3 x i32] [i32 42, i32 43, i32 44], 2
; CHECK: [[RES:%.*]] = insertvalue [2 x i32] [[RESTMP]], i32 [[VAL2]], 1
; CHECK: ret [2 x i32] [[RES]]
; CHECK-LABEL: define void @test_can_shrink_arrays()
define internal [3 x i32] @can_shrink_arrays() {
ret [3 x i32] [i32 42, i32 43, i32 44]
}
define void @test_can_shrink_arrays() {
%res = call [3 x i32] @can_shrink_arrays()
%res.0 = extractvalue [3 x i32] %res, 0
call void @callee(i32 %res.0)
%res.2 = extractvalue [3 x i32] %res, 2
call void @callee(i32 %res.2)
ret void
}
; Case 5: %in gets passed directly to the return. It should mark be marked as
; used if *any* of the return values are, not just if value 0 is.
; CHECK-LABEL: define internal i32 @ret_applies_to_all({ i32, i32 } %in)
; CHECK: [[RET:%.*]] = extractvalue { i32, i32 } %in, 1
; CHECK: ret i32 [[RET]]
define internal {i32, i32} @ret_applies_to_all({i32, i32} %in) {
ret {i32, i32} %in
}
define i32 @test_ret_applies_to_all() {
%val = call {i32, i32} @ret_applies_to_all({i32, i32} {i32 42, i32 43})
%ret = extractvalue {i32, i32} %val, 1
ret i32 %ret
}
; Case 6: When considering @mid, the return instruciton has sub-value 0
; unconditionally live, but 1 only conditionally live. Since at that level we're
; applying the results to the whole of %res, this means %res is live and cannot
; be reduced. There is scope for further optimisation here (though not visible
; in this test-case).
; CHECK-LABEL: define internal { i8*, i32 } @inner()
define internal {i8*, i32} @mid() {
%res = call {i8*, i32} @inner()
%intval = extractvalue {i8*, i32} %res, 1
%tst = icmp eq i32 %intval, 42
br i1 %tst, label %true, label %true
true:
ret {i8*, i32} %res
}
define internal {i8*, i32} @inner() {
ret {i8*, i32} {i8* null, i32 42}
}
define internal i8 @outer() {
%res = call {i8*, i32} @mid()
%resptr = extractvalue {i8*, i32} %res, 0
%val = load i8, i8* %resptr
ret i8 %val
}
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