On Fri, Dec 14, 2018 at 12:27 AM Ilia Mirkin <imir...@alum.mit.edu> wrote:
>
> On Thu, Dec 13, 2018 at 6:14 PM Karol Herbst <kher...@redhat.com> wrote:
> >
> > gives me an performance boost of 0.2% in pixmark_piano on my gk106, gm204
> > and
> > gp107.
> >
> > changes in shader-db:
> >
> > total instructions in shared programs : 7614782 -> 7614782 (0.00%)
> > total cvt instructions in shared programs : 139343 -> 95856 (-31.21%)
> > total gprs used in shared programs : 798045 -> 798045 (0.00%)
> > total shared used in shared programs : 639636 -> 639636 (0.00%)
> > total local used in shared programs : 24648 -> 24648 (0.00%)
> > total bytes used in shared programs : 81330696 -> 81330696 (0.00%)
> >
> > local shared gpr inst cvts bytes
> > helped 0 0 0 0 14037 0
> > hurt 0 0 0 0 0 0
> >
> > Signed-off-by: Karol Herbst <kher...@redhat.com>
> > ---
> > .../nouveau/codegen/nv50_ir_lowering_nvc0.cpp | 55 +++++++++++++++++++
> > .../nouveau/codegen/nv50_ir_lowering_nvc0.h | 1 +
> > 2 files changed, 56 insertions(+)
> >
> > diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> > b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> > index 295497be2f9..267fef0898d 100644
> > --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> > +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> > @@ -719,6 +719,58 @@ NVC0LegalizePostRA::propagateJoin(BasicBlock *bb)
> > bb->remove(bb->getEntry());
> > }
> >
> > +// replaces instructions which would end up as f2f or i2i with faster
> > +// alternatives:
> > +// - abs(a) -> add(0, abs a)
> > +// - neg(a) -> add(0, neg a)
> > +// - neg(abs a) -> add(0, neg abs a)
> > +// - sat(a) -> sat add(0, a)
> > +void
> > +NVC0LegalizePostRA::replaceCvt(Instruction *cvt)
> > +{
> > + if (typeSizeof(cvt->sType) == 8)
>
> != 4
>
> Otherwise you're just asking for trouble.
>
> > + return;
> > + if (cvt->sType != cvt->dType)
> > + return;
> > + // we could make it work, but in this case we have optimizations
> > disabled
> > + // and we don't really care either way.
> > + if (cvt->src(0).getFile() == FILE_IMMEDIATE)
> > + return;
> > +
> > + switch (cvt->op) {
> > + case OP_ABS:
> > + if (cvt->src(0).mod)
> > + break;
> > + if (!isFloatType(cvt->sType))
>
> Why? What's wrong with IABS -> IADD? Similar question for OP_NEG.
>
iadd can't have abs modifiers
> > + break;
> > + cvt->op = OP_ADD;
> > + cvt->moveSources(0, 1);
>
> These two lines, along with moveSources are always repeated. Would be
> nice to centralize this somehow.
yeah.. just didn't figure out a super nice way to do that except
checking twice for valid opcodes :/
>
> > + cvt->src(1).mod = NV50_IR_MOD_ABS;
> > + cvt->setSrc(0, rZero);
> > + cvt->src(0).mod = 0;
> > + break;
> > + case OP_NEG:
> > + if (cvt->src(0).mod && (cvt->src(0).mod.neg() ||
> > !isFloatType(cvt->sType)))
> > + break;
> > + cvt->op = OP_ADD;
> > + cvt->moveSources(0, 1);
> > + cvt->src(1).mod = cvt->src(0).mod ? NV50_IR_MOD_NEG_ABS :
> > NV50_IR_MOD_NEG;
> > + cvt->setSrc(0, rZero);
> > + cvt->src(0).mod = 0;
> > + break;
> > + case OP_SAT:
> > + if (cvt->src(0).mod)
> > + break;
> > + cvt->op = OP_ADD;
> > + cvt->moveSources(0, 1);
> > + cvt->setSrc(0, rZero);
> > + cvt->saturate = true;
> > + break;
> > + default:
> > + break;
> > + }
> > +}
> > +
> > bool
> > NVC0LegalizePostRA::visit(BasicBlock *bb)
> > {
> > @@ -758,6 +810,9 @@ NVC0LegalizePostRA::visit(BasicBlock *bb)
> > next = hi;
> > }
> >
> > + if (i->isCvt())
> > + replaceCvt(i);
> > +
> > if (i->op != OP_MOV && i->op != OP_PFETCH)
> > replaceZero(i);
> > }
> > diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> > b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> > index e0f50ab0904..4679c56471b 100644
> > --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> > +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.h
> > @@ -81,6 +81,7 @@ private:
> > virtual bool visit(Function *);
> > virtual bool visit(BasicBlock *);
> >
> > + void replaceCvt(Instruction *);
> > void replaceZero(Instruction *);
> > bool tryReplaceContWithBra(BasicBlock *);
> > void propagateJoin(BasicBlock *);
> > --
> > 2.19.2
> >
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