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[SystemZ] Use XC for a memset of 0

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190130 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Richard Sandiford 2013-09-06 10:25:07 +00:00
parent 4598bd53ab
commit 867f9501f6
2 changed files with 58 additions and 61 deletions
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29
lib/Target/SystemZ/SystemZSelectionDAGInfo.cpp
View File

@ -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<ConstantSDNode>(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<ConstantSDNode>(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();
}

90
test/CodeGen/SystemZ/memset-03.ll
View File

@ -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 256, i32 1, i1 false)
ret void
}
; 256 bytes, i64 version.
define void @f38(i8 *%dest) {
; CHECK-LABEL: f38:
; CHECK: xc 0(256,%r2), 0(%r2)
; CHECK: br %r14
call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 256, i32 1, i1 false)
ret void
}
; 257 bytes, i32 version. We need two MVCs.
define void @f39(i8 *%dest) {
; CHECK-LABEL: f39:
; 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 257, i32 1, i1 false)
ret void
}
; 257 bytes, i64 version.
define void @f38(i8 *%dest) {
; CHECK-LABEL: f38:
; CHECK: mvi 0(%r2), 0
; CHECK: mvc 1(256,%r2), 0(%r2)
define void @f40(i8 *%dest) {
; CHECK-LABEL: f40:
; 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 257, i32 1, i1 false)
ret void
}
; 258 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: br %r14
call void @llvm.memset.p0i8.i32(i8 *%dest, i8 0, i32 258, i32 1, i1 false)
ret void
}
; 258 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: br %r14
call void @llvm.memset.p0i8.i64(i8 *%dest, i8 0, i64 258, i32 1, i1 false)
ret void
}