fa24213928
Fixes #85560. We can forward `memcpy` as long as the actual memory location being copied have not been altered. alive2: https://alive2.llvm.org/ce/z/q9JaHV
29 lines
1.2 KiB
LLVM
29 lines
1.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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; RUN: opt < %s -passes=memcpyopt,instcombine -S -verify-memoryssa | FileCheck --check-prefix=CUSTOM %s
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; RUN: opt < %s -O2 -S | FileCheck --check-prefix=O2 %s
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; Check that we eliminate all `memcpy` calls in this function.
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define void @memcpy_forward_back_with_offset(ptr %arg) {
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; CUSTOM-LABEL: define void @memcpy_forward_back_with_offset(
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; CUSTOM-SAME: ptr [[ARG:%.*]]) {
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; CUSTOM-NEXT: store i8 1, ptr [[ARG]], align 1
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; CUSTOM-NEXT: ret void
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;
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; O2-LABEL: define void @memcpy_forward_back_with_offset(
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; O2-SAME: ptr nocapture writeonly [[ARG:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
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; O2-NEXT: store i8 1, ptr [[ARG]], align 1
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; O2-NEXT: ret void
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;
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%i = alloca [753 x i8], align 1
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%i1 = alloca [754 x i8], align 1
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call void @llvm.memcpy.p0.p0.i64(ptr %i1, ptr %arg, i64 754, i1 false)
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%i2 = getelementptr inbounds i8, ptr %i1, i64 1
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call void @llvm.memcpy.p0.p0.i64(ptr %i, ptr %i2, i64 753, i1 false)
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store i8 1, ptr %arg, align 1
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%i3 = getelementptr inbounds i8, ptr %arg, i64 1
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call void @llvm.memcpy.p0.p0.i64(ptr %i3, ptr %i, i64 753, i1 false)
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ret void
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}
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declare void @llvm.memcpy.p0.p0.i64(ptr, ptr, i64, i1)
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