forked from OSchip/llvm-project
31 lines
1.2 KiB
LLVM
31 lines
1.2 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-unknown-linux -O2 | FileCheck %s
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; This test checks that:
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; (1) mempcpy is lowered as memcpy, and
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; (2) its return value is DST+N i.e. the dst pointer adjusted by the copy size.
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; To keep the testing of (2) independent of the exact instructions used to
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; adjust the dst pointer, DST+N is explicitly computed and stored to a global
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; variable G before the mempcpy call. This instance of DST+N causes the repeat
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; DST+N done in the context of the return value of mempcpy to be redundant, and
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; the first instance to be reused as the return value. This allows the check for
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; (2) to be expressed as verifying that the MOV to store DST+N to G and
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; the MOV to copy DST+N to %rax use the same source register.
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; Also see mempcpy-32.ll
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@G = common dso_local global i8* null, align 8
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; CHECK-LABEL: RET_MEMPCPY:
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; CHECK: movq [[REG:%r[a-z0-9]+]], {{.*}}G
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; CHECK: callq {{.*}}memcpy
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; CHECK: movq [[REG]], %rax
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;
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define dso_local i8* @RET_MEMPCPY(i8* %DST, i8* %SRC, i64 %N) {
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%add.ptr = getelementptr inbounds i8, i8* %DST, i64 %N
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store i8* %add.ptr, i8** @G, align 8
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%call = tail call i8* @mempcpy(i8* %DST, i8* %SRC, i64 %N)
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ret i8* %call
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}
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declare i8* @mempcpy(i8*, i8*, i64)
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