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If we can, lower the multiply part of a umulo/smulo call to a libcall

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with an invalid type then split the result and perform the overflow check
normally.

Fixes the 32-bit parts of rdar://8622122 and rdar://8774702.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123864 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Christopher 2011-01-20 00:29:24 +00:00
parent e449d1f189
commit 38a18261b9
2 changed files with 41 additions and 8 deletions
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35
lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
View File

@ -3181,14 +3181,8 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node,
BottomHalf = DAG.getNode(Ops[isSigned][1], dl, DAG.getVTList(VT, VT), LHS,
RHS);
TopHalf = BottomHalf.getValue(1);
} else {
// FIXME: We should be able to fall back to a libcall with an illegal
// type in some cases.
// Also, we can fall back to a division in some cases, but that's a big
// performance hit in the general case.
assert(TLI.isTypeLegal(EVT::getIntegerVT(*DAG.getContext(),
VT.getSizeInBits() * 2)) &&
"Don't know how to expand this operation yet!");
} else if (TLI.isTypeLegal(EVT::getIntegerVT(*DAG.getContext(),
VT.getSizeInBits() * 2))) {
EVT WideVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits() * 2);
LHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, LHS);
RHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, RHS);
@ -3197,6 +3191,31 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node,
DAG.getIntPtrConstant(0));
TopHalf = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, VT, Tmp1,
DAG.getIntPtrConstant(1));
} else {
// We can fall back to a libcall with an illegal type for the MUL if we
// have a libcall big enough.
// Also, we can fall back to a division in some cases, but that's a big
// performance hit in the general case.
EVT WideVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits() * 2);
RTLIB::Libcall LC = RTLIB::UNKNOWN_LIBCALL;
if (WideVT == MVT::i16)
LC = RTLIB::MUL_I16;
else if (WideVT == MVT::i32)
LC = RTLIB::MUL_I32;
else if (WideVT == MVT::i64)
LC = RTLIB::MUL_I64;
else if (WideVT == MVT::i128)
LC = RTLIB::MUL_I128;
assert(LC != RTLIB::UNKNOWN_LIBCALL && "Cannot expand this operation!");
LHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, LHS);
RHS = DAG.getNode(Ops[isSigned][2], dl, WideVT, RHS);
SDValue Ops[2] = { LHS, RHS };
SDValue Ret = ExpandLibCall(LC, Node, Ops);
BottomHalf = DAG.getNode(ISD::TRUNCATE, dl, VT, Ret);
TopHalf = DAG.getNode(ISD::SRL, dl, Ret.getValueType(), Ret,
DAG.getConstant(VT.getSizeInBits(), TLI.getPointerTy()));
TopHalf = DAG.getNode(ISD::TRUNCATE, dl, VT, TopHalf);
}
if (isSigned) {
Tmp1 = DAG.getConstant(VT.getSizeInBits() - 1, TLI.getShiftAmountTy());

14
test/CodeGen/ARM/umulo-32.ll Normal file
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@ -0,0 +1,14 @@
; RUN: llc < %s -mtriple=thumbv6-apple-darwin | FileCheck %s
%umul.ty = type { i32, i1 }
define i32 @func(i32 %a) nounwind {
; CHECK: func
; CHECK: muldi3
%tmp0 = tail call %umul.ty @llvm.umul.with.overflow.i32(i32 %a, i32 37)
%tmp1 = extractvalue %umul.ty %tmp0, 0
%tmp2 = select i1 undef, i32 -1, i32 %tmp1
ret i32 %tmp2
}
declare %umul.ty @llvm.umul.with.overflow.i32(i32, i32) nounwind readnone