[llvm] r300960 - use repmovsb when optimizing forminsize
Clement Courbet via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 21 02:20:55 PDT 2017
Author: courbet
Date: Fri Apr 21 04:20:55 2017
New Revision: 300960
URL: http://llvm.org/viewvc/llvm-project?rev=300960&view=rev
Log:
use repmovsb when optimizing forminsize
Modified:
llvm/trunk/lib/Target/X86/X86SelectionDAGInfo.cpp
llvm/trunk/test/CodeGen/X86/memcpy-struct-by-value.ll
Modified: llvm/trunk/lib/Target/X86/X86SelectionDAGInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86SelectionDAGInfo.cpp?rev=300960&r1=300959&r2=300960&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86SelectionDAGInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86SelectionDAGInfo.cpp Fri Apr 21 04:20:55 2017
@@ -181,6 +181,24 @@ SDValue X86SelectionDAGInfo::EmitTargetC
return Chain;
}
+namespace {
+
+// Represents a cover of a buffer of SizeVal bytes with blocks of size
+// AVT, as well as how many bytes remain (BytesLeft is always smaller than
+// the block size).
+struct RepMovsRepeats {
+ RepMovsRepeats(const uint64_t SizeVal, const MVT& AVT) {
+ const unsigned UBytes = AVT.getSizeInBits() / 8;
+ Count = SizeVal / UBytes;
+ BytesLeft = SizeVal % UBytes;
+ }
+
+ unsigned Count;
+ unsigned BytesLeft;
+};
+
+} // namespace
+
SDValue X86SelectionDAGInfo::EmitTargetCodeForMemcpy(
SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
SDValue Size, unsigned Align, bool isVolatile, bool AlwaysInline,
@@ -231,14 +249,18 @@ SDValue X86SelectionDAGInfo::EmitTargetC
// QWORD aligned
AVT = Subtarget.is64Bit() ? MVT::i64 : MVT::i32;
- unsigned UBytes = AVT.getSizeInBits() / 8;
- unsigned CountVal = SizeVal / UBytes;
- SDValue Count = DAG.getIntPtrConstant(CountVal, dl);
- unsigned BytesLeft = SizeVal % UBytes;
+ RepMovsRepeats Repeats(SizeVal, AVT);
+ if (Repeats.BytesLeft > 0 &&
+ DAG.getMachineFunction().getFunction()->optForMinSize()) {
+ // When agressively optimizing for size, avoid generating the code to handle
+ // BytesLeft.
+ AVT = MVT::i8;
+ Repeats = RepMovsRepeats(SizeVal, AVT);
+ }
SDValue InFlag;
Chain = DAG.getCopyToReg(Chain, dl, Subtarget.is64Bit() ? X86::RCX : X86::ECX,
- Count, InFlag);
+ DAG.getIntPtrConstant(Repeats.Count, dl), InFlag);
InFlag = Chain.getValue(1);
Chain = DAG.getCopyToReg(Chain, dl, Subtarget.is64Bit() ? X86::RDI : X86::EDI,
Dst, InFlag);
@@ -253,9 +275,9 @@ SDValue X86SelectionDAGInfo::EmitTargetC
SmallVector<SDValue, 4> Results;
Results.push_back(RepMovs);
- if (BytesLeft) {
+ if (Repeats.BytesLeft) {
// Handle the last 1 - 7 bytes.
- unsigned Offset = SizeVal - BytesLeft;
+ unsigned Offset = SizeVal - Repeats.BytesLeft;
EVT DstVT = Dst.getValueType();
EVT SrcVT = Src.getValueType();
EVT SizeVT = Size.getValueType();
@@ -266,7 +288,8 @@ SDValue X86SelectionDAGInfo::EmitTargetC
DAG.getNode(ISD::ADD, dl, SrcVT, Src,
DAG.getConstant(Offset, dl,
SrcVT)),
- DAG.getConstant(BytesLeft, dl, SizeVT),
+ DAG.getConstant(Repeats.BytesLeft, dl,
+ SizeVT),
Align, isVolatile, AlwaysInline, false,
DstPtrInfo.getWithOffset(Offset),
SrcPtrInfo.getWithOffset(Offset)));
Modified: llvm/trunk/test/CodeGen/X86/memcpy-struct-by-value.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/memcpy-struct-by-value.ll?rev=300960&r1=300959&r2=300960&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/memcpy-struct-by-value.ll (original)
+++ llvm/trunk/test/CodeGen/X86/memcpy-struct-by-value.ll Fri Apr 21 04:20:55 2017
@@ -17,3 +17,29 @@ define void @test1(%struct.large* nocapt
; FAST: rep;movsb
; HASWELL: rep;movsb
}
+
+define void @test2(%struct.large* nocapture %x) nounwind minsize {
+ call void @foo(%struct.large* align 8 byval %x)
+ ret void
+
+; ALL-LABEL: test2:
+; NOFAST: rep;movsq
+; GENERIC: rep;movsq
+; FAST: rep;movsb
+; HASWELL: rep;movsb
+}
+
+%struct.large_oddsize = type { [4095 x i8] }
+
+declare void @foo_oddsize(%struct.large_oddsize* align 8 byval) nounwind
+
+define void @test3(%struct.large_oddsize* nocapture %x) nounwind minsize {
+ call void @foo_oddsize(%struct.large_oddsize* align 8 byval %x)
+ ret void
+
+; ALL-LABEL: test3:
+; NOFAST: rep;movsb
+; GENERIC: rep;movsb
+; FAST: rep;movsb
+; HASWELL: rep;movsb
+}
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