4e89d1199c
When src/dest passed into memset/memcpy is null: ``` len == 0: this call is a noop. len != 0: the behavior is undefined. ``` See also https://llvm.org/docs/LangRef.html#llvm-memset-intrinsics Alive2: https://alive2.llvm.org/ce/z/tJeRNL This patch converts these mem intrinsic calls into an assumption `len == 0` to mitigate code-size bloat caused by JumpThreading.
78 lines
2.5 KiB
LLVM
78 lines
2.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
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; RUN: opt -S -passes=instcombine < %s | FileCheck %s
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define void @memset_null(i64 %len) {
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; CHECK-LABEL: define void @memset_null(
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; CHECK-SAME: i64 [[LEN:%.*]]) {
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[LEN]], 0
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; CHECK-NEXT: call void @llvm.assume(i1 [[TMP1]])
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; CHECK-NEXT: ret void
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;
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call void @llvm.memset.p0.i64(ptr null, i8 0, i64 %len, i1 false)
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ret void
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}
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define void @memset_null_ub() {
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; CHECK-LABEL: define void @memset_null_ub() {
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; CHECK-NEXT: store i64 poison, ptr null, align 4294967296
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; CHECK-NEXT: ret void
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;
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call void @llvm.memset.p0.i64(ptr null, i8 0, i64 8, i1 false)
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ret void
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}
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define void @memcpy_null_src(ptr %dst, i64 %len) {
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; CHECK-LABEL: define void @memcpy_null_src(
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; CHECK-SAME: ptr [[DST:%.*]], i64 [[LEN:%.*]]) {
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[LEN]], 0
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; CHECK-NEXT: call void @llvm.assume(i1 [[TMP1]])
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; CHECK-NEXT: ret void
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;
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call void @llvm.memcpy.p0.i64(ptr %dst, ptr null, i64 %len, i1 false)
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ret void
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}
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define void @memmove_null_src(ptr %dst, i64 %len) {
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; CHECK-LABEL: define void @memmove_null_src(
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; CHECK-SAME: ptr [[DST:%.*]], i64 [[LEN:%.*]]) {
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[LEN]], 0
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; CHECK-NEXT: call void @llvm.assume(i1 [[TMP1]])
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; CHECK-NEXT: ret void
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;
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call void @llvm.memmove.p0.i64(ptr %dst, ptr null, i64 %len, i1 false)
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ret void
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}
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define void @memset_element_atomic(i64 %len) {
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; CHECK-LABEL: define void @memset_element_atomic(
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; CHECK-SAME: i64 [[LEN:%.*]]) {
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i64 [[LEN]], 0
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; CHECK-NEXT: call void @llvm.assume(i1 [[TMP1]])
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; CHECK-NEXT: ret void
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;
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call void @llvm.memset.element.unordered.atomic.p0.i64(ptr align 1 null, i8 0, i64 %len, i32 1)
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ret void
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}
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; negative tests
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define void @memset_null_volatile(i64 %len) {
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; CHECK-LABEL: define void @memset_null_volatile(
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; CHECK-SAME: i64 [[LEN:%.*]]) {
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; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr null, i8 0, i64 [[LEN]], i1 true)
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; CHECK-NEXT: ret void
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;
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call void @llvm.memset.p0.i64(ptr null, i8 0, i64 %len, i1 true)
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ret void
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}
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define void @memset_null_is_defined(i64 %len) null_pointer_is_valid {
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; CHECK-LABEL: define void @memset_null_is_defined(
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; CHECK-SAME: i64 [[LEN:%.*]]) #[[ATTR0:[0-9]+]] {
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; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4294967296 null, i8 0, i64 [[LEN]], i1 false)
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; CHECK-NEXT: ret void
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;
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call void @llvm.memset.p0.i64(ptr null, i8 0, i64 %len, i1 false)
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ret void
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}
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