From 867f9501f64c12a693bed624c53e8104421917a9 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Fri, 6 Sep 2013 10:25:07 +0000 Subject: [PATCH] [SystemZ] Use XC for a memset of 0 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190130 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../SystemZ/SystemZSelectionDAGInfo.cpp | 29 +++++--- test/CodeGen/SystemZ/memset-03.ll | 68 +++++++------------ 2 files changed, 47 insertions(+), 50 deletions(-) diff --git a/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp b/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp index dc2f225acb2..3b43cbdb3e7 100644 --- a/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp +++ b/lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp @@ -25,10 +25,14 @@ SystemZSelectionDAGInfo(const SystemZTargetMachine &TM) SystemZSelectionDAGInfo::~SystemZSelectionDAGInfo() { } -// Use MVC to copy Size bytes from Src to Dest, deciding whether to use -// a loop or straight-line code. -static SDValue emitMVC(SelectionDAG &DAG, SDLoc DL, SDValue Chain, - SDValue Dst, SDValue Src, uint64_t Size) { +// Decide whether it is best to use a loop or straight-line code for +// a block operation of Size bytes with source address Src and destination +// address Dest. Sequence is the opcode to use for straight-line code +// (such as MVC) and Loop is the opcode to use for loops (such as MVC_LOOP). +// Return the chain for the completed operation. +static SDValue emitMemMem(SelectionDAG &DAG, SDLoc DL, unsigned Sequence, + unsigned Loop, SDValue Chain, SDValue Dst, + SDValue Src, uint64_t Size) { EVT PtrVT = Src.getValueType(); // The heuristic we use is to prefer loops for anything that would // require 7 or more MVCs. With these kinds of sizes there isn't @@ -42,10 +46,10 @@ static SDValue emitMVC(SelectionDAG &DAG, SDLoc DL, SDValue Chain, // The next value up, 6 * 256, can be implemented in the same // number of straight-line MVCs as 6 * 256 - 1. if (Size > 6 * 256) - return DAG.getNode(SystemZISD::MVC_LOOP, DL, MVT::Other, Chain, Dst, Src, + return DAG.getNode(Loop, DL, MVT::Other, Chain, Dst, Src, DAG.getConstant(Size, PtrVT), DAG.getConstant(Size / 256, PtrVT)); - return DAG.getNode(SystemZISD::MVC, DL, MVT::Other, Chain, Dst, Src, + return DAG.getNode(Sequence, DL, MVT::Other, Chain, Dst, Src, DAG.getConstant(Size, PtrVT)); } @@ -59,7 +63,8 @@ EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc DL, SDValue Chain, return SDValue(); if (ConstantSDNode *CSize = dyn_cast(Size)) - return emitMVC(DAG, DL, Chain, Dst, Src, CSize->getZExtValue()); + return emitMemMem(DAG, DL, SystemZISD::MVC, SystemZISD::MVC_LOOP, + Chain, Dst, Src, CSize->getZExtValue()); return SDValue(); } @@ -130,13 +135,21 @@ EmitTargetCodeForMemset(SelectionDAG &DAG, SDLoc DL, SDValue Chain, } } assert(Bytes >= 2 && "Should have dealt with 0- and 1-byte cases already"); + + // Handle the special case of a memset of 0, which can use XC. + ConstantSDNode *CByte = dyn_cast(Byte); + if (CByte && CByte->getZExtValue() == 0) + return emitMemMem(DAG, DL, SystemZISD::XC, SystemZISD::XC_LOOP, + Chain, Dst, Dst, Bytes); + // Copy the byte to the first location and then use MVC to copy // it to the rest. Chain = DAG.getStore(Chain, DL, Byte, Dst, DstPtrInfo, false, false, Align); SDValue DstPlus1 = DAG.getNode(ISD::ADD, DL, PtrVT, Dst, DAG.getConstant(1, PtrVT)); - return emitMVC(DAG, DL, Chain, DstPlus1, Dst, Bytes - 1); + return emitMemMem(DAG, DL, SystemZISD::MVC, SystemZISD::MVC_LOOP, + Chain, DstPlus1, Dst, Bytes - 1); } return SDValue(); } diff --git a/test/CodeGen/SystemZ/memset-03.ll b/test/CodeGen/SystemZ/memset-03.ll index 3f954c4f79f..a95f89fc7c0 100644 --- a/test/CodeGen/SystemZ/memset-03.ll +++ b/test/CodeGen/SystemZ/memset-03.ll @@ -140,8 +140,7 @@ define void @f14(i8 *%dest) { ; 7 bytes, i32 version. define void @f15(i8 *%dest) { ; CHECK-LABEL: f15: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(6,%r2), 0(%r2) +; CHECK: xc 0(7,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 7, i32 1, i1 false) ret void @@ -150,8 +149,7 @@ define void @f15(i8 *%dest) { ; 7 bytes, i64 version. define void @f16(i8 *%dest) { ; CHECK-LABEL: f16: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(6,%r2), 0(%r2) +; CHECK: xc 0(7,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 7, i32 1, i1 false) ret void @@ -218,8 +216,7 @@ define void @f22(i8 *%dest) { ; 11 bytes, i32 version. define void @f23(i8 *%dest) { ; CHECK-LABEL: f23: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(10,%r2), 0(%r2) +; CHECK: xc 0(11,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 11, i32 1, i1 false) ret void @@ -228,8 +225,7 @@ define void @f23(i8 *%dest) { ; 11 bytes, i64 version. define void @f24(i8 *%dest) { ; CHECK-LABEL: f24: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(10,%r2), 0(%r2) +; CHECK: xc 0(11,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 11, i32 1, i1 false) ret void @@ -258,8 +254,7 @@ define void @f26(i8 *%dest) { ; 13 bytes, i32 version. define void @f27(i8 *%dest) { ; CHECK-LABEL: f27: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(12,%r2), 0(%r2) +; CHECK: xc 0(13,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 13, i32 1, i1 false) ret void @@ -268,8 +263,7 @@ define void @f27(i8 *%dest) { ; 13 bytes, i64 version. define void @f28(i8 *%dest) { ; CHECK-LABEL: f28: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(12,%r2), 0(%r2) +; CHECK: xc 0(13,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 13, i32 1, i1 false) ret void @@ -278,8 +272,7 @@ define void @f28(i8 *%dest) { ; 14 bytes, i32 version. define void @f29(i8 *%dest) { ; CHECK-LABEL: f29: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(13,%r2), 0(%r2) +; CHECK: xc 0(14,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 14, i32 1, i1 false) ret void @@ -288,8 +281,7 @@ define void @f29(i8 *%dest) { ; 14 bytes, i64 version. define void @f30(i8 *%dest) { ; CHECK-LABEL: f30: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(13,%r2), 0(%r2) +; CHECK: xc 0(14,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 14, i32 1, i1 false) ret void @@ -298,8 +290,7 @@ define void @f30(i8 *%dest) { ; 15 bytes, i32 version. define void @f31(i8 *%dest) { ; CHECK-LABEL: f31: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(14,%r2), 0(%r2) +; CHECK: xc 0(15,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 15, i32 1, i1 false) ret void @@ -308,8 +299,7 @@ define void @f31(i8 *%dest) { ; 15 bytes, i64 version. define void @f32(i8 *%dest) { ; CHECK-LABEL: f32: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(14,%r2), 0(%r2) +; CHECK: xc 0(15,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 15, i32 1, i1 false) ret void @@ -338,8 +328,7 @@ define void @f34(i8 *%dest) { ; 17 bytes, i32 version. define void @f35(i8 *%dest) { ; CHECK-LABEL: f35: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(16,%r2), 0(%r2) +; CHECK: xc 0(17,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 17, i32 1, i1 false) ret void @@ -348,51 +337,46 @@ define void @f35(i8 *%dest) { ; 17 bytes, i64 version. define void @f36(i8 *%dest) { ; CHECK-LABEL: f36: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(16,%r2), 0(%r2) +; CHECK: xc 0(17,%r2), 0(%r2) ; CHECK: br %r14 call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 17, i32 1, i1 false) ret void } -; 257 bytes, i32 version. +; 256 bytes, i32 version. define void @f37(i8 *%dest) { ; CHECK-LABEL: f37: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(256,%r2), 0(%r2) +; CHECK: xc 0(256,%r2), 0(%r2) ; CHECK: br %r14 - call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 257, i32 1, i1 false) + call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 256, i32 1, i1 false) ret void } -; 257 bytes, i64 version. +; 256 bytes, i64 version. define void @f38(i8 *%dest) { ; CHECK-LABEL: f38: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(256,%r2), 0(%r2) +; CHECK: xc 0(256,%r2), 0(%r2) ; CHECK: br %r14 - call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 257, i32 1, i1 false) + call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 256, i32 1, i1 false) ret void } -; 258 bytes, i32 version. We need two MVCs. +; 257 bytes, i32 version. We need two MVCs. define void @f39(i8 *%dest) { ; CHECK-LABEL: f39: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(256,%r2), 0(%r2) -; CHECK: mvc 257(1,%r2), 256(%r2) +; CHECK: xc 0(256,%r2), 0(%r2) +; CHECK: xc 256(1,%r2), 256(%r2) ; CHECK: br %r14 - call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 258, i32 1, i1 false) + call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 257, i32 1, i1 false) ret void } -; 258 bytes, i64 version. +; 257 bytes, i64 version. define void @f40(i8 *%dest) { ; CHECK-LABEL: f40: -; CHECK: mvi 0(%r2), 0 -; CHECK: mvc 1(256,%r2), 0(%r2) -; CHECK: mvc 257(1,%r2), 256(%r2) +; CHECK: xc 0(256,%r2), 0(%r2) +; CHECK: xc 256(1,%r2), 256(%r2) ; CHECK: br %r14 - call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 258, i32 1, i1 false) + call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 257, i32 1, i1 false) ret void } -- 2.34.1