nv50/ir: fix texture grad for cubemaps

We were ignoring the partial derivatives on the last dim.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp

@@ -1897,7 +1897,7 @@ Converter::handleTEX(Value *dst[4], int R, int S, int L, int C, int Dx, int Dy)
       shd = fetchSrc(C >> 4, C & 3);
 
    if (texi->op == OP_TXD) {
-      for (c = 0; c < tgt.getDim(); ++c) {
+      for (c = 0; c < tgt.getDim() + tgt.isCube(); ++c) {
          texi->dPdx[c].set(fetchSrc(Dx >> 4, (Dx & 3) + c));
          texi->dPdy[c].set(fetchSrc(Dy >> 4, (Dy & 3) + c));
       }

src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_gm107.cpp

@@ -57,7 +57,7 @@ GM107LoweringPass::handleManualTXD(TexInstruction *i)
    Instruction *tex, *add;
    Value *zero = bld.loadImm(bld.getSSA(), 0);
    int l, c;
-   const int dim = i->tex.target.getDim();
+   const int dim = i->tex.target.getDim() + i->tex.target.isCube();
    const int array = i->tex.target.isArray();
 
    i->op = OP_TEX; // no need to clone dPdx/dPdy later

src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nv50.cpp

@@ -911,7 +911,7 @@ NV50LoweringPreSSA::handleTXD(TexInstruction *i)
    Instruction *tex;
    Value *zero = bld.loadImm(bld.getSSA(), 0);
    int l, c;
-   const int dim = i->tex.target.getDim();
+   const int dim = i->tex.target.getDim() + i->tex.target.isCube();
 
    handleTEX(i);
    i->op = OP_TEX; // no need to clone dPdx/dPdy later

src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp

@@ -870,7 +870,7 @@ NVC0LoweringPass::handleManualTXD(TexInstruction *i)
    Instruction *tex;
    Value *zero = bld.loadImm(bld.getSSA(), 0);
    int l, c;
-   const int dim = i->tex.target.getDim();
+   const int dim = i->tex.target.getDim() + i->tex.target.isCube();
    const int array = i->tex.target.isArray();
 
    i->op = OP_TEX; // no need to clone dPdx/dPdy later
@@ -917,7 +917,7 @@ NVC0LoweringPass::handleManualTXD(TexInstruction *i)
 bool
 NVC0LoweringPass::handleTXD(TexInstruction *txd)
 {
-   int dim = txd->tex.target.getDim();
+   int dim = txd->tex.target.getDim() + txd->tex.target.isCube();
    unsigned arg = txd->tex.target.getArgCount();
    unsigned expected_args = arg;
    const int chipset = prog->getTarget()->getChipset();
@@ -937,8 +937,7 @@ NVC0LoweringPass::handleTXD(TexInstruction *txd)
 
    if (expected_args > 4 ||
        dim > 2 ||
-       txd->tex.target.isShadow() ||
-       txd->tex.target.isCube())
+       txd->tex.target.isShadow())
       txd->op = OP_TEX;
 
    handleTEX(txd);