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|
; RUN: opt < %s -S -early-cse | FileCheck %s
; RUN: opt < %s -S -passes=early-cse | FileCheck %s
declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) nounwind readonly
declare void @llvm.invariant.end.p0i8({}*, i64, i8* nocapture) nounwind
; Check that we do load-load forwarding over invariant.start, since it does not
; clobber memory
define i8 @test_bypass1(i8 *%P) {
; CHECK-LABEL: @test_bypass1(
; CHECK-NEXT: %V1 = load i8, i8* %P
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
; CHECK-NEXT: ret i8 0
%V1 = load i8, i8* %P
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
%V2 = load i8, i8* %P
%Diff = sub i8 %V1, %V2
ret i8 %Diff
}
; Trivial Store->load forwarding over invariant.start
define i8 @test_bypass2(i8 *%P) {
; CHECK-LABEL: @test_bypass2(
; CHECK-NEXT: store i8 42, i8* %P
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
; CHECK-NEXT: ret i8 42
store i8 42, i8* %P
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
%V1 = load i8, i8* %P
ret i8 %V1
}
; We can DSE over invariant.start calls, since the first store to
; %P is valid, and the second store is actually unreachable based on semantics
; of invariant.start.
define void @test_bypass3(i8* %P) {
; CHECK-LABEL: @test_bypass3(
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
; CHECK-NEXT: store i8 60, i8* %P
store i8 50, i8* %P
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
store i8 60, i8* %P
ret void
}
; FIXME: Now the first store can actually be eliminated, since there is no read within
; the invariant region, between start and end.
define void @test_bypass4(i8* %P) {
; CHECK-LABEL: @test_bypass4(
; CHECK-NEXT: store i8 50, i8* %P
; CHECK-NEXT: %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
; CHECK-NEXT: call void @llvm.invariant.end.p0i8({}* %i, i64 1, i8* %P)
; CHECK-NEXT: store i8 60, i8* %P
store i8 50, i8* %P
%i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %P)
call void @llvm.invariant.end.p0i8({}* %i, i64 1, i8* %P)
store i8 60, i8* %P
ret void
}
declare void @clobber()
declare {}* @llvm.invariant.start.p0i32(i64 %size, i32* nocapture %ptr)
declare void @llvm.invariant.end.p0i32({}*, i64, i32* nocapture) nounwind
define i32 @test_before_load(i32* %p) {
; CHECK-LABEL: @test_before_load
; CHECK: ret i32 0
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_before_clobber(i32* %p) {
; CHECK-LABEL: @test_before_clobber
; CHECK: ret i32 0
%v1 = load i32, i32* %p
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_duplicate_scope(i32* %p) {
; CHECK-LABEL: @test_duplicate_scope
; CHECK: ret i32 0
%v1 = load i32, i32* %p
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_unanalzyable_load(i32* %p) {
; CHECK-LABEL: @test_unanalzyable_load
; CHECK: ret i32 0
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_negative_after_clobber(i32* %p) {
; CHECK-LABEL: @test_negative_after_clobber
; CHECK: ret i32 %sub
%v1 = load i32, i32* %p
call void @clobber()
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_merge(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_merge
; CHECK: ret i32 0
%v1 = load i32, i32* %p
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
br i1 %cnd, label %merge, label %taken
taken:
call void @clobber()
br label %merge
merge:
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_negative_after_mergeclobber(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_negative_after_mergeclobber
; CHECK: ret i32 %sub
%v1 = load i32, i32* %p
br i1 %cnd, label %merge, label %taken
taken:
call void @clobber()
br label %merge
merge:
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
; In theory, this version could work, but earlycse is incapable of
; merging facts along distinct paths.
define i32 @test_false_negative_merge(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_false_negative_merge
; CHECK: ret i32 %sub
%v1 = load i32, i32* %p
br i1 %cnd, label %merge, label %taken
taken:
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
br label %merge
merge:
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_merge_unanalyzable_load(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_merge_unanalyzable_load
; CHECK: ret i32 0
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
%v1 = load i32, i32* %p
br i1 %cnd, label %merge, label %taken
taken:
call void @clobber()
br label %merge
merge:
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define void @test_dse_before_load(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_dse_before_load
; CHECK-NOT: store
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
store i32 %v1, i32* %p
ret void
}
define void @test_dse_after_load(i32* %p, i1 %cnd) {
; CHECK-LABEL: @test_dse_after_load
; CHECK-NOT: store
%v1 = load i32, i32* %p
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @clobber()
store i32 %v1, i32* %p
ret void
}
; In this case, we have a false negative since MemoryLocation is implicitly
; typed due to the user of a Value to represent the address. Note that other
; passes will canonicalize away the bitcasts in this example.
define i32 @test_false_negative_types(i32* %p) {
; CHECK-LABEL: @test_false_negative_types
; CHECK: ret i32 %sub
call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%pf = bitcast i32* %p to float*
%v2f = load float, float* %pf
%v2 = bitcast float %v2f to i32
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_negative_size1(i32* %p) {
; CHECK-LABEL: @test_negative_size1
; CHECK: ret i32 %sub
call {}* @llvm.invariant.start.p0i32(i64 3, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_negative_size2(i32* %p) {
; CHECK-LABEL: @test_negative_size2
; CHECK: ret i32 %sub
call {}* @llvm.invariant.start.p0i32(i64 0, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_negative_scope(i32* %p) {
; CHECK-LABEL: @test_negative_scope
; CHECK: ret i32 %sub
%scope = call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
call void @llvm.invariant.end.p0i32({}* %scope, i64 4, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
define i32 @test_false_negative_scope(i32* %p) {
; CHECK-LABEL: @test_false_negative_scope
; CHECK: ret i32 %sub
%scope = call {}* @llvm.invariant.start.p0i32(i64 4, i32* %p)
%v1 = load i32, i32* %p
call void @clobber()
%v2 = load i32, i32* %p
call void @llvm.invariant.end.p0i32({}* %scope, i64 4, i32* %p)
%sub = sub i32 %v1, %v2
ret i32 %sub
}
; Invariant load defact starts an invariant.start scope of the appropriate size
define i32 @test_invariant_load_scope(i32* %p) {
; CHECK-LABEL: @test_invariant_load_scope
; CHECK: ret i32 0
%v1 = load i32, i32* %p, !invariant.load !{}
call void @clobber()
%v2 = load i32, i32* %p
%sub = sub i32 %v1, %v2
ret i32 %sub
}
|
