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Do some peephole optimizations to remove pointless VMOVs from Neon to integer

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registers that arise from argument shuffling with the soft float ABI. These
instructions are particularly slow on Cortex A8. This fixes one half of
<rdar://problem/8674845>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128759 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Cameron Zwarich 2011-04-02 02:40:43 +00:00
parent ed3caf9086
commit 4071a71112
2 changed files with 42 additions and 0 deletions
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31
lib/Target/ARM/ARMISelLowering.cpp
View File

@ -5561,6 +5561,37 @@ static SDValue PerformVMOVRRDCombine(SDNode *N,
SDValue InDouble = N->getOperand(0);
if (InDouble.getOpcode() == ARMISD::VMOVDRR)
return DCI.CombineTo(N, InDouble.getOperand(0), InDouble.getOperand(1));
// vmovrrd(load f64) -> (load i32), (load i32)
SDNode *InNode = InDouble.getNode();
if (ISD::isNormalLoad(InNode) && InNode->hasOneUse() &&
InNode->getValueType(0) == MVT::f64 &&
InNode->getOperand(1).getOpcode() == ISD::FrameIndex &&
!cast<LoadSDNode>(InNode)->isVolatile()) {
// TODO: Should this be done for non-FrameIndex operands?
LoadSDNode *LD = cast<LoadSDNode>(InNode);
SelectionDAG &DAG = DCI.DAG;
DebugLoc DL = LD->getDebugLoc();
SDValue BasePtr = LD->getBasePtr();
SDValue NewLD1 = DAG.getLoad(MVT::i32, DL, LD->getChain(), BasePtr,
LD->getPointerInfo(), LD->isVolatile(),
LD->isNonTemporal(), LD->getAlignment());
SDValue OffsetPtr = DAG.getNode(ISD::ADD, DL, MVT::i32, BasePtr,
DAG.getConstant(4, MVT::i32));
SDValue NewLD2 = DAG.getLoad(MVT::i32, DL, NewLD1.getValue(1), OffsetPtr,
LD->getPointerInfo(), LD->isVolatile(),
LD->isNonTemporal(),
std::min(4U, LD->getAlignment() / 2));
DAG.ReplaceAllUsesOfValueWith(SDValue(LD, 1), NewLD2.getValue(1));
SDValue Result = DCI.CombineTo(N, NewLD1, NewLD2);
DCI.RemoveFromWorklist(LD);
DAG.DeleteNode(LD);
return Result;
}
return SDValue();
}

11
test/CodeGen/ARM/fp-arg-shuffle.ll Normal file
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@ -0,0 +1,11 @@
; RUN: llc < %s -march=arm -mattr=+neon -float-abi=soft | FileCheck %s
; CHECK: function1
; CHECK-NOT: vmov r
define double @function1(double %a, double %b, double %c, double %d, double %e, double %f) nounwind noinline ssp {
entry:
%call = tail call double @function2(double %f, double %e, double %d, double %c, double %b, double %a) nounwind
ret double %call
}
declare double @function2(double, double, double, double, double, double)