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~40% faster vector shl <4 x i32> on SSE 4.1 Larger improvements for smaller types coming in future patches.

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For:

define <2 x i64> @shl(<4 x i32> %r, <4 x i32> %a) nounwind readnone ssp {
entry:
  %shl = shl <4 x i32> %r, %a                     ; <<4 x i32>> [#uses=1]
  %tmp2 = bitcast <4 x i32> %shl to <2 x i64>     ; <<2 x i64>> [#uses=1]
  ret <2 x i64> %tmp2
}

We get:

_shl:                                   ## @shl
	pslld	$23, %xmm1
	paddd	LCPI0_0, %xmm1
	cvttps2dq	%xmm1, %xmm1
	pmulld	%xmm1, %xmm0
	ret

Instead of:

_shl:                                   ## @shl
	pshufd	$3, %xmm0, %xmm2
	movd	%xmm2, %eax
	pshufd	$3, %xmm1, %xmm2
	movd	%xmm2, %ecx
	shll	%cl, %eax
	movd	%eax, %xmm2
	pshufd	$1, %xmm0, %xmm3
	movd	%xmm3, %eax
	pshufd	$1, %xmm1, %xmm3
	movd	%xmm3, %ecx
	shll	%cl, %eax
	movd	%eax, %xmm3
	punpckldq	%xmm2, %xmm3
	movd	%xmm0, %eax
	movd	%xmm1, %ecx
	shll	%cl, %eax
	movd	%eax, %xmm2
	movhlps	%xmm0, %xmm0
	movd	%xmm0, %eax
	movhlps	%xmm1, %xmm1
	movd	%xmm1, %ecx
	shll	%cl, %eax
	movd	%eax, %xmm0
	punpckldq	%xmm0, %xmm2
	movdqa	%xmm2, %xmm0
	punpckldq	%xmm3, %xmm0
	ret

llvm-svn: 109549
This commit is contained in:
Nate Begeman 2010-07-27 22:37:06 +00:00
parent 8c197e5dbb
commit 068e932975
3 changed files with 48 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
lib/Target/X86/X86ISelLowering.cpp
View File

@ -838,6 +838,9 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
// FIXME: Do we need to handle scalar-to-vector here?
setOperationAction(ISD::MUL, MVT::v4i32, Legal);
// Can turn SHL into an integer multiply.
setOperationAction(ISD::SHL, MVT::v4i32, Custom);
// i8 and i16 vectors are custom , because the source register and source
// source memory operand types are not the same width. f32 vectors are
// custom since the immediate controlling the insert encodes additional
@ -7498,6 +7501,35 @@ SDValue X86TargetLowering::LowerMUL_V2I64(SDValue Op, SelectionDAG &DAG) const {
return Res;
}
SDValue X86TargetLowering::LowerSHL(SDValue Op, SelectionDAG &DAG) const {
EVT VT = Op.getValueType();
DebugLoc dl = Op.getDebugLoc();
SDValue R = Op.getOperand(0);
assert(Subtarget->hasSSE41() && "Cannot lower SHL without SSE4.1 or later");
assert(VT == MVT::v4i32 && "Only know how to lower v4i32");
Op = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
DAG.getConstant(Intrinsic::x86_sse2_pslli_d, MVT::i32),
Op.getOperand(1), DAG.getConstant(23, MVT::i32));
std::vector<Constant*> CV;
LLVMContext *Context = DAG.getContext();
CV.push_back(ConstantInt::get(*Context, APInt(32, 0x3f800000U)));
CV.push_back(ConstantInt::get(*Context, APInt(32, 0x3f800000U)));
CV.push_back(ConstantInt::get(*Context, APInt(32, 0x3f800000U)));
CV.push_back(ConstantInt::get(*Context, APInt(32, 0x3f800000U)));
Constant *C = ConstantVector::get(CV);
SDValue CPIdx = DAG.getConstantPool(C, getPointerTy(), 16);
SDValue Addend = DAG.getLoad(VT, dl, DAG.getEntryNode(), CPIdx,
PseudoSourceValue::getConstantPool(), 0,
false, false, 16);
Op = DAG.getNode(ISD::ADD, dl, VT, Op, Addend);
Op = DAG.getNode(ISD::BIT_CONVERT, dl, MVT::v4f32, Op);
Op = DAG.getNode(ISD::FP_TO_SINT, dl, VT, Op);
return DAG.getNode(ISD::MUL, dl, VT, Op, R);
}
SDValue X86TargetLowering::LowerXALUO(SDValue Op, SelectionDAG &DAG) const {
// Lower the "add/sub/mul with overflow" instruction into a regular ins plus
@ -7730,6 +7762,7 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
case ISD::CTLZ: return LowerCTLZ(Op, DAG);
case ISD::CTTZ: return LowerCTTZ(Op, DAG);
case ISD::MUL: return LowerMUL_V2I64(Op, DAG);
case ISD::SHL: return LowerSHL(Op, DAG);
case ISD::SADDO:
case ISD::UADDO:
case ISD::SSUBO:

1
lib/Target/X86/X86ISelLowering.h
View File

@ -723,6 +723,7 @@ namespace llvm {
SDValue LowerCTLZ(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerCTTZ(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerMUL_V2I64(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerSHL(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerXALUO(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerCMP_SWAP(SDValue Op, SelectionDAG &DAG) const;

14
test/CodeGen/X86/vec_shift4.ll Normal file
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@ -0,0 +1,14 @@
; RUN: llc < %s -march=x86 -mattr=+sse41 | FileCheck %s
define <2 x i64> @shl(<4 x i32> %r, <4 x i32> %a) nounwind readnone ssp {
entry:
; CHECK-NOT: shll
; CHECK: pslld
; CHECK: paddd
; CHECK: cvttps2dq
; CHECK: pmulld
%shl = shl <4 x i32> %r, %a ; <<4 x i32>> [#uses=1]
%tmp2 = bitcast <4 x i32> %shl to <2 x i64> ; <<2 x i64>> [#uses=1]
ret <2 x i64> %tmp2
}