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.
> + 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.
> + 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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