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[AVX] If the data which is going to be saved is already in two XMM registers 

(for example, after integer operation), do not pack the registers into a YMM
before saving. Its better to save as two XMM registers.

Before:
                vinsertf128         $1, %xmm3, %ymm0, %ymm3
                vinsertf128         $0, %xmm1, %ymm3, %ymm1
                vmovaps              %ymm1, 416(%rsp)

After:
                vmovaps              %xmm3, 416+16(%rsp)
                vmovaps              %xmm1, 416(%rsp)

llvm-svn: 137308
This commit is contained in:
Nadav Rotem 2011-08-11 16:41:21 +00:00
parent aa51684318
commit 1542d5a00a
2 changed files with 40 additions and 0 deletions
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23
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -12589,6 +12589,29 @@ static SDValue PerformSTORECombine(SDNode *N, SelectionDAG &DAG,
EVT VT = St->getValue().getValueType();
EVT StVT = St->getMemoryVT();
DebugLoc dl = St->getDebugLoc();
SDValue StoredVal = St->getOperand(1);
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
// If we are saving a concatination of two XMM registers, perform two stores.
if (VT.getSizeInBits() == 256 &&
StoredVal.getNode()->getOpcode() == ISD::CONCAT_VECTORS &&
StoredVal.getNumOperands() == 2) {
SDValue Value0 = StoredVal.getOperand(0);
SDValue Value1 = StoredVal.getOperand(1);
SDValue Stride = DAG.getConstant(16, TLI.getPointerTy());
SDValue Ptr0 = St->getBasePtr();
SDValue Ptr1 = DAG.getNode(ISD::ADD, dl, Ptr0.getValueType(), Ptr0, Stride);
SDValue Ch0 = DAG.getStore(St->getChain(), dl, Value0, Ptr0,
St->getPointerInfo(), St->isVolatile(),
St->isNonTemporal(), St->getAlignment());
SDValue Ch1 = DAG.getStore(St->getChain(), dl, Value1, Ptr1,
St->getPointerInfo(), St->isVolatile(),
St->isNonTemporal(), St->getAlignment());
return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Ch0, Ch1);
}
// Optimize trunc store (of multiple scalars) to shuffle and store.
// First, pack all of the elements in one place. Next, store to memory

17
llvm/test/CodeGen/X86/avx-insert.ll Normal file
View File

@ -0,0 +1,17 @@
; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7-avx -mattr=+avx | FileCheck %s
; It is faster to make two saves, if the data is already in XMM registers. For
; example, after making an integer operation.
define void @double_save(<4 x i32>* %Ap, <4 x i32>* %Bp, <8 x i32>* %P) nounwind ssp {
entry:
; CHECK: movaps
; CHECK: movaps
; CHECK: movaps
; CHECK: movaps
%A = load <4 x i32>* %Ap
%B = load <4 x i32>* %Bp
%Z = shufflevector <4 x i32>%A, <4 x i32>%B, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
store <8 x i32> %Z, <8 x i32>* %P, align 16
ret void
}