[llvm] r233681 - [SDAG] Move TRUNCATE splitting logic into a helper, and use
James Molloy
james at jamesmolloy.co.uk
Thu Apr 16 01:43:02 PDT 2015
Hi Ahmed,
Thanks for your comments. I've re-looked at the code, and I completely
misunderstood what an FTRUNC node was - I confused it with FP_ROUND.
So yes, FTRUNC should just use the generic unary op splitting, and wide FP
truncations should not have an FTRUNC node planted but an (FP_ROUND $x, 0).
I also agree with the HalfVT problem. Thanks for noticing both of these! I
attach a patch which I think fixes all the issues, could you please review
it?
I've added tests for v4{f,i}64->v4{i,f}16 to exercise this logic.
Cheers,
James
On Thu, 16 Apr 2015 at 02:51 Ahmed Bougacha <ahmed.bougacha at gmail.com>
wrote:
> Hi James,
>
> I got around to looking at this, and I have two concerns.
>
> First, is FTRUNC really a truncating conversion, and isn't it just a
> unary op? It returns the exact same type, but removes the fractional
> part.
> The code should never fire currently, as I don't think we generate
> FTRUNCs with different in/out types. It might make sense for
> "(FP_ROUND x, 1)" though, where it's fine to do the double-rounding.
>
> Second, for INT_TO_FP, the current logic (this is fixable I think)
> explicitly creates an integer type as HalfElementVT, but it should
> really be an FP type (if not, you should get stuff like "uitofp int ->
> int").
> The code should only fire when there's a 4x size difference; the only
> case I can think of is f64/i64 -> f16, or i128 -> f32, if that's
> actually legal somewhere.
>
> -Ahmed
>
>
> On Tue, Mar 31, 2015 at 3:20 AM, James Molloy <james.molloy at arm.com>
> wrote:
> > Author: jamesm
> > Date: Tue Mar 31 05:20:58 2015
> > New Revision: 233681
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=233681&view=rev
> > Log:
> > [SDAG] Move TRUNCATE splitting logic into a helper, and use
> > it more liberally.
> >
> > SplitVecOp_TRUNCATE has logic for recursively splitting oversize vectors
> > that need more than one round of splitting to become legal. There are
> many
> > other ISD nodes that could benefit from this logic, so factor it out and
> > use it for FP_TO_UINT,FP_TO_SINT,SINT_TO_FP,UINT_TO_FP and FTRUNC.
> >
> > Added:
> > llvm/trunk/test/CodeGen/AArch64/vcvt-oversize.ll
> > Modified:
> > llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
> > llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
> > llvm/trunk/test/CodeGen/AArch64/arm64-convert-v4f64.ll
> > llvm/trunk/test/CodeGen/ARM/vcvt.ll
> >
> > Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h?rev=233681&r1=233680&r2=233681&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h (original)
> > +++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h Tue Mar 31
> 05:20:58 2015
> > @@ -593,6 +593,7 @@ private:
> > bool SplitVectorOperand(SDNode *N, unsigned OpNo);
> > SDValue SplitVecOp_VSELECT(SDNode *N, unsigned OpNo);
> > SDValue SplitVecOp_UnaryOp(SDNode *N);
> > + SDValue SplitVecOp_TruncateHelper(SDNode *N, unsigned TruncateOp);
> >
> > SDValue SplitVecOp_BITCAST(SDNode *N);
> > SDValue SplitVecOp_EXTRACT_SUBVECTOR(SDNode *N);
> > @@ -600,7 +601,6 @@ private:
> > SDValue SplitVecOp_STORE(StoreSDNode *N, unsigned OpNo);
> > SDValue SplitVecOp_MSTORE(MaskedStoreSDNode *N, unsigned OpNo);
> > SDValue SplitVecOp_CONCAT_VECTORS(SDNode *N);
> > - SDValue SplitVecOp_TRUNCATE(SDNode *N);
> > SDValue SplitVecOp_VSETCC(SDNode *N);
> > SDValue SplitVecOp_FP_ROUND(SDNode *N);
> >
> >
> > Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp?rev=233681&r1=233680&r2=233681&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
> (original)
> > +++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp Tue Mar
> 31 05:20:58 2015
> > @@ -1293,7 +1293,9 @@ bool DAGTypeLegalizer::SplitVectorOperan
> > case ISD::EXTRACT_SUBVECTOR: Res = SplitVecOp_EXTRACT_SUBVECTOR(N);
> break;
> > case ISD::EXTRACT_VECTOR_ELT:Res =
> SplitVecOp_EXTRACT_VECTOR_ELT(N); break;
> > case ISD::CONCAT_VECTORS: Res = SplitVecOp_CONCAT_VECTORS(N);
> break;
> > - case ISD::TRUNCATE: Res = SplitVecOp_TRUNCATE(N); break;
> > + case ISD::TRUNCATE:
> > + Res = SplitVecOp_TruncateHelper(N, ISD::TRUNCATE);
> > + break;
> > case ISD::FP_ROUND: Res = SplitVecOp_FP_ROUND(N); break;
> > case ISD::STORE:
> > Res = SplitVecOp_STORE(cast<StoreSDNode>(N), OpNo);
> > @@ -1304,20 +1306,32 @@ bool DAGTypeLegalizer::SplitVectorOperan
> > case ISD::VSELECT:
> > Res = SplitVecOp_VSELECT(N, OpNo);
> > break;
> > - case ISD::CTTZ:
> > - case ISD::CTLZ:
> > - case ISD::CTPOP:
> > - case ISD::FP_EXTEND:
> > case ISD::FP_TO_SINT:
> > case ISD::FP_TO_UINT:
> > + if (N->getValueType(0).bitsLT(N->getOperand(0)->getValueType(0)))
> > + Res = SplitVecOp_TruncateHelper(N, ISD::TRUNCATE);
> > + else
> > + Res = SplitVecOp_UnaryOp(N);
> > + break;
> > case ISD::SINT_TO_FP:
> > case ISD::UINT_TO_FP:
> > - case ISD::FTRUNC:
> > + if (N->getValueType(0).bitsLT(N->getOperand(0)->getValueType(0)))
> > + Res = SplitVecOp_TruncateHelper(N, ISD::FTRUNC);
> > + else
> > + Res = SplitVecOp_UnaryOp(N);
> > + break;
> > + case ISD::CTTZ:
> > + case ISD::CTLZ:
> > + case ISD::CTPOP:
> > + case ISD::FP_EXTEND:
> > case ISD::SIGN_EXTEND:
> > case ISD::ZERO_EXTEND:
> > case ISD::ANY_EXTEND:
> > Res = SplitVecOp_UnaryOp(N);
> > break;
> > + case ISD::FTRUNC:
> > + Res = SplitVecOp_TruncateHelper(N, ISD::FTRUNC);
> > + break;
> > }
> > }
> >
> > @@ -1581,7 +1595,8 @@ SDValue DAGTypeLegalizer::SplitVecOp_CON
> > return DAG.getNode(ISD::BUILD_VECTOR, DL, N->getValueType(0), Elts);
> > }
> >
> > -SDValue DAGTypeLegalizer::SplitVecOp_TRUNCATE(SDNode *N) {
> > +SDValue DAGTypeLegalizer::SplitVecOp_TruncateHelper(SDNode *N,
> > + unsigned
> TruncateOp) {
> > // The result type is legal, but the input type is illegal. If
> splitting
> > // ends up with the result type of each half still being legal, just
> > // do that. If, however, that would result in an illegal result type,
> > @@ -1624,8 +1639,8 @@ SDValue DAGTypeLegalizer::SplitVecOp_TRU
> > EVT HalfElementVT = EVT::getIntegerVT(*DAG.getContext(),
> InElementSize/2);
> > EVT HalfVT = EVT::getVectorVT(*DAG.getContext(), HalfElementVT,
> > NumElements/2);
> > - SDValue HalfLo = DAG.getNode(ISD::TRUNCATE, DL, HalfVT, InLoVec);
> > - SDValue HalfHi = DAG.getNode(ISD::TRUNCATE, DL, HalfVT, InHiVec);
> > + SDValue HalfLo = DAG.getNode(N->getOpcode(), DL, HalfVT, InLoVec);
> > + SDValue HalfHi = DAG.getNode(N->getOpcode(), DL, HalfVT, InHiVec);
> > // Concatenate them to get the full intermediate truncation result.
> > EVT InterVT = EVT::getVectorVT(*DAG.getContext(), HalfElementVT,
> NumElements);
> > SDValue InterVec = DAG.getNode(ISD::CONCAT_VECTORS, DL, InterVT,
> HalfLo,
> > @@ -1634,7 +1649,7 @@ SDValue DAGTypeLegalizer::SplitVecOp_TRU
> > // type. This should normally be something that ends up being legal
> directly,
> > // but in theory if a target has very wide vectors and an annoyingly
> > // restricted set of legal types, this split can chain to build
> things up.
> > - return DAG.getNode(ISD::TRUNCATE, DL, OutVT, InterVec);
> > + return DAG.getNode(TruncateOp, DL, OutVT, InterVec);
> > }
> >
> > SDValue DAGTypeLegalizer::SplitVecOp_VSETCC(SDNode *N) {
> >
> > Modified: llvm/trunk/test/CodeGen/AArch64/arm64-convert-v4f64.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/arm64-convert-v4f64.ll?rev=233681&r1=233680&r2=233681&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/CodeGen/AArch64/arm64-convert-v4f64.ll (original)
> > +++ llvm/trunk/test/CodeGen/AArch64/arm64-convert-v4f64.ll Tue Mar 31
> 05:20:58 2015
> > @@ -3,11 +3,11 @@
> >
> > define <4 x i16> @fptosi_v4f64_to_v4i16(<4 x double>* %ptr) {
> > ; CHECK: fptosi_v4f64_to_v4i16
> > -; CHECK-DAG: fcvtzs v[[LHS:[0-9]+]].2d, v1.2d
> > -; CHECK-DAG: fcvtzs v[[RHS:[0-9]+]].2d, v0.2d
> > -; CHECK-DAG: xtn v[[LHS_NA:[0-9]+]].2s, v[[LHS]].2d
> > -; CHECK-DAG: xtn v[[RHS_NA:[0-9]+]].2s, v[[RHS]].2d
> > -; CHECK: uzp1 v0.4h, v[[RHS_NA]].4h, v[[LHS_NA]].4h
> > +; CHECK-DAG: fcvtzs v[[LHS:[0-9]+]].2d, v0.2d
> > +; CHECK-DAG: fcvtzs v[[RHS:[0-9]+]].2d, v1.2d
> > +; CHECK-DAG: xtn v[[MID:[0-9]+]].2s, v[[LHS]].2d
> > +; CHECK-DAG: xtn2 v[[MID]].4s, v[[RHS]].2d
> > +; CHECK: xtn v0.4h, v[[MID]].4s
> > %tmp1 = load <4 x double>, <4 x double>* %ptr
> > %tmp2 = fptosi <4 x double> %tmp1 to <4 x i16>
> > ret <4 x i16> %tmp2
> > @@ -19,13 +19,13 @@ define <8 x i8> @fptosi_v4f64_to_v4i8(<8
> > ; CHECK-DAG: fcvtzs v[[CONV1:[0-9]+]].2d, v1.2d
> > ; CHECK-DAG: fcvtzs v[[CONV2:[0-9]+]].2d, v2.2d
> > ; CHECK-DAG: fcvtzs v[[CONV3:[0-9]+]].2d, v3.2d
> > -; CHECK-DAG: xtn v[[NA0:[0-9]+]].2s, v[[CONV0]].2d
> > -; CHECK-DAG: xtn v[[NA1:[0-9]+]].2s, v[[CONV1]].2d
> > ; CHECK-DAG: xtn v[[NA2:[0-9]+]].2s, v[[CONV2]].2d
> > -; CHECK-DAG: xtn v[[NA3:[0-9]+]].2s, v[[CONV3]].2d
> > -; CHECK-DAG: uzp1 v[[TMP1:[0-9]+]].4h, v[[CONV1]].4h, v[[CONV0]].4h
> > -; CHECK-DAG: uzp1 v[[TMP2:[0-9]+]].4h, v[[CONV3]].4h, v[[CONV2]].4h
> > -; CHECK: uzp1 v0.8b, v[[TMP2]].8b, v[[TMP1]].8b
> > +; CHECK-DAG: xtn2 v[[NA2]].4s, v[[CONV3]].2d
> > +; CHECK-DAG: xtn v[[NA0:[0-9]+]].2s, v[[CONV0]].2d
> > +; CHECK-DAG: xtn2 v[[NA0]].4s, v[[CONV1]].2d
> > +; CHECK-DAG: xtn v[[TMP1:[0-9]+]].4h, v[[NA0]].4s
> > +; CHECK-DAG: xtn2 v[[TMP1]].8h, v[[NA2]].4s
> > +; CHECK: xtn v0.8b, v[[TMP1]].8h
> > %tmp1 = load <8 x double>, <8 x double>* %ptr
> > %tmp2 = fptosi <8 x double> %tmp1 to <8 x i8>
> > ret <8 x i8> %tmp2
> >
> > Added: llvm/trunk/test/CodeGen/AArch64/vcvt-oversize.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/vcvt-oversize.ll?rev=233681&view=auto
> >
> ==============================================================================
> > --- llvm/trunk/test/CodeGen/AArch64/vcvt-oversize.ll (added)
> > +++ llvm/trunk/test/CodeGen/AArch64/vcvt-oversize.ll Tue Mar 31 05:20:58
> 2015
> > @@ -0,0 +1,16 @@
> > +; RUN: llc -mtriple=aarch64 < %s | FileCheck %s
> > +
> > +define <8 x i8> @float_to_i8(<8 x float>* %in) {
> > +; CHECK-LABEL: float_to_i8:
> > +; CHECK-DAG: fadd v[[LSB:[0-9]+]].4s, v0.4s, v0.4s
> > +; CHECK-DAG: fadd v[[MSB:[0-9]+]].4s, v1.4s, v1.4s
> > +; CHECK-DAG: fcvtzu v[[LSB2:[0-9]+]].4s, v[[LSB]].4s
> > +; CHECK-DAG: fcvtzu v[[MSB2:[0-9]+]].4s, v[[MSB]].4s
> > +; CHECK-DAG: xtn v[[TMP:[0-9]+]].4h, v[[LSB]].4s
> > +; CHECK-DAG: xtn2 v[[TMP]].8h, v[[MSB]].4s
> > +; CHECK-DAG: xtn v0.8b, v[[TMP]].8h
> > + %l = load <8 x float>, <8 x float>* %in
> > + %scale = fmul <8 x float> %l, <float 2.0, float 2.0, float 2.0, float
> 2.0, float 2.0, float 2.0, float 2.0, float 2.0>
> > + %conv = fptoui <8 x float> %scale to <8 x i8>
> > + ret <8 x i8> %conv
> > +}
> >
> > Modified: llvm/trunk/test/CodeGen/ARM/vcvt.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/vcvt.ll?rev=233681&r1=233680&r2=233681&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/test/CodeGen/ARM/vcvt.ll (original)
> > +++ llvm/trunk/test/CodeGen/ARM/vcvt.ll Tue Mar 31 05:20:58 2015
> > @@ -180,8 +180,8 @@ define <2 x i64> @fix_float_to_i64(<2 x
> >
> > define <4 x i16> @fix_double_to_i16(<4 x double> %in) {
> > ; CHECK-LABEL: fix_double_to_i16:
> > -; CHECK: vcvt.s32.f64
> > -; CHECK: vcvt.s32.f64
> > +; CHECK: vcvt.u32.f64
> > +; CHECK: vcvt.u32.f64
> >
> > %scale = fmul <4 x double> %in, <double 2.0, double 2.0, double 2.0,
> double 2.0>
> > %conv = fptoui <4 x double> %scale to <4 x i16>
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150416/5ccd3e22/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Fix-TRUNCATE-splitting-helper-logic.patch
Type: application/octet-stream
Size: 6394 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150416/5ccd3e22/attachment.obj>
More information about the llvm-commits
mailing list