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[MemCpyOpt] Add additional call slot capture tests (NFC) 

One test shows a miscompile when bitcasts are involved, the others
cases where we can perform the optimization despite a capture.
This commit is contained in:
Nikita Popov 2021-12-13 10:08:50 +01:00
parent 9feeb2fb61
commit 396370e889
1 changed files with 67 additions and 3 deletions
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70
llvm/test/Transforms/MemCpyOpt/capturing-func.ll
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@ -5,7 +5,11 @@ target datalayout = "e"
declare void @foo(i8*)
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i1) nounwind
declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture)
; Check that the transformation isn't applied if the called function can
; capture the pointer argument (i.e. the nocapture attribute isn't present)
define void @test() {
; CHECK-LABEL: @test(
; CHECK-NEXT: [[PTR1:%.*]] = alloca i8, align 1
@ -21,7 +25,67 @@ define void @test() {
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr1, i8* %ptr2, i32 1, i1 false)
call void @foo(i8* %ptr1)
ret void
; Check that the transformation isn't applied if the called function can
; capture the pointer argument (i.e. the nocapture attribute isn't present)
}
; Same as previous test, but with a bitcasted argument.
; TODO: Call slot optimization should not be applied here.
define void @test_bitcast() {
; CHECK-LABEL: @test_bitcast(
; CHECK-NEXT: [[PTR1:%.*]] = alloca [2 x i8], align 1
; CHECK-NEXT: [[PTR2:%.*]] = alloca [2 x i8], align 1
; CHECK-NEXT: [[PTR1_CAST:%.*]] = bitcast [2 x i8]* [[PTR1]] to i8*
; CHECK-NEXT: [[PTR2_CAST:%.*]] = bitcast [2 x i8]* [[PTR2]] to i8*
; CHECK-NEXT: [[PTR11:%.*]] = bitcast [2 x i8]* [[PTR1]] to i8*
; CHECK-NEXT: call void @foo(i8* [[PTR11]])
; CHECK-NEXT: call void @foo(i8* [[PTR1_CAST]])
; CHECK-NEXT: ret void
;
%ptr1 = alloca [2 x i8]
%ptr2 = alloca [2 x i8]
%ptr1.cast = bitcast [2 x i8]* %ptr1 to i8*
%ptr2.cast = bitcast [2 x i8]* %ptr2 to i8*
call void @foo(i8* %ptr2.cast)
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr1.cast, i8* %ptr2.cast, i32 2, i1 false)
call void @foo(i8* %ptr1.cast)
ret void
}
; Lifetime of %ptr2 ends before the potential use of the capture in the second
; call.
define void @test_lifetime_end() {
; CHECK-LABEL: @test_lifetime_end(
; CHECK-NEXT: [[PTR1:%.*]] = alloca i8, align 1
; CHECK-NEXT: [[PTR2:%.*]] = alloca i8, align 1
; CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 1, i8* [[PTR2]])
; CHECK-NEXT: call void @foo(i8* [[PTR2]])
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* [[PTR1]], i8* [[PTR2]], i32 1, i1 false)
; CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 1, i8* [[PTR2]])
; CHECK-NEXT: call void @foo(i8* [[PTR1]])
; CHECK-NEXT: ret void
;
%ptr1 = alloca i8
%ptr2 = alloca i8
call void @llvm.lifetime.start.p0i8(i64 1, i8* %ptr2)
call void @foo(i8* %ptr2)
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr1, i8* %ptr2, i32 1, i1 false)
call void @llvm.lifetime.end.p0i8(i64 1, i8* %ptr2)
call void @foo(i8* %ptr1)
ret void
}
; Lifetime of %ptr2 ends before any potential use of the capture because we
; return from the function.
define void @test_function_end() {
; CHECK-LABEL: @test_function_end(
; CHECK-NEXT: [[PTR1:%.*]] = alloca i8, align 1
; CHECK-NEXT: [[PTR2:%.*]] = alloca i8, align 1
; CHECK-NEXT: call void @foo(i8* [[PTR2]])
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* [[PTR1]], i8* [[PTR2]], i32 1, i1 false)
; CHECK-NEXT: ret void
;
%ptr1 = alloca i8
%ptr2 = alloca i8
call void @foo(i8* %ptr2)
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr1, i8* %ptr2, i32 1, i1 false)
ret void
}