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| author | Clement Courbet <courbet@google.com> | 2017-04-21 09:20:39 +0000 |
|---|---|---|
| committer | Clement Courbet <courbet@google.com> | 2017-04-21 09:20:39 +0000 |
| commit | 1ce3b82dea8eb35e77974fc9d97f9a08c690c53d (patch) | |
| tree | 10718c7c21b90322462a789d671de895ccb18d54 /llvm/test/CodeGen/X86/memcpy-struct-by-value.ll | |
| parent | f8a964252643c4e65d0c091105cc9d4cbe813690 (diff) | |
| download | bcm5719-llvm-1ce3b82dea8eb35e77974fc9d97f9a08c690c53d.tar.gz bcm5719-llvm-1ce3b82dea8eb35e77974fc9d97f9a08c690c53d.zip | |
X86 memcpy: use REPMOVSB instead of REPMOVS{Q,D,W} for inline copies
when the subtarget has fast strings.
This has two advantages:
- Speed is improved. For example, on Haswell thoughput improvements increase
linearly with size from 256 to 512 bytes, after which they plateau:
(e.g. 1% for 260 bytes, 25% for 400 bytes, 40% for 508 bytes).
- Code is much smaller (no need to handle boundaries).
llvm-svn: 300957
Diffstat (limited to 'llvm/test/CodeGen/X86/memcpy-struct-by-value.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/memcpy-struct-by-value.ll | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/memcpy-struct-by-value.ll b/llvm/test/CodeGen/X86/memcpy-struct-by-value.ll new file mode 100644 index 00000000000..4bb022e9332 --- /dev/null +++ b/llvm/test/CodeGen/X86/memcpy-struct-by-value.ll @@ -0,0 +1,15 @@ +; RUN: llc -mtriple=x86_64-linux-gnu -mattr=-fast-string < %s -o - | FileCheck %s --check-prefix=ALL --check-prefix=NOFAST +; RUN: llc -mtriple=x86_64-linux-gnu -mattr=+fast-string < %s -o - | FileCheck %s --check-prefix=ALL --check-prefix=FAST + +%struct.large = type { [4096 x i8] } + +declare void @foo(%struct.large* align 8 byval) nounwind + +define void @test1(%struct.large* nocapture %x) nounwind { + call void @foo(%struct.large* align 8 byval %x) + ret void + +; ALL-LABEL: test1: +; NOFAST: rep;movsq +; FAST: rep;movsb +} |
