nvc0/ir: be careful about propagating very large offsets into const load

Indirect constbuf indexing works by using very large offsets. However if
an indirect constbuf index load is const-propagated, it becomes a very
large const offset. Take that into account when legalizing the SSA by
moving the high parts of that offset into the file index. Also disallow
very large (or small) indices on most other instructions.

This fixes regressions in ubo_array_indexing/*-two-arrays piglit tests.

Fixes: abd326e81b (nv50/ir: propagate indirect loads into instructions)
Signed-off-by: Ilia Mirkin <[email protected]>

4 files changed, 19 insertions, 1 deletions

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 6530078b938..dc1ab769b98 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
@@ -540,6 +540,12 @@ NVC0LegalizePostRA::visit(BasicBlock *bb)
          // It seems like barriers are never required for tessellation since
          // the warp size is 32, and there are always at most 32 tcs threads.
          bb->remove(i);
+      } else
+      if (i->op == OP_LOAD && i->subOp == NV50_IR_SUBOP_LDC_IS) {
+         int offset = i->src(0).get()->reg.data.offset;
+         if (abs(offset) > 0x10000)
+            i->src(0).get()->reg.fileIndex += offset >> 16;
+         i->src(0).get()->reg.data.offset = (int)(short)offset;
       } else {
          // TODO: Move this to before register allocation for operations that
          // need the $c register !
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target.h b/src/gallium/drivers/nouveau/codegen/nv50_ir_target.h
index 673f8811ff3..e6e1912adae 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target.h
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target.h
@@ -192,7 +192,7 @@ public:
    virtual bool insnCanLoad(const Instruction *insn, int s,
                             const Instruction *ld) const = 0;
    virtual bool insnCanLoadOffset(const Instruction *insn, int s,
-                                  int offset) const { return true; }
+                                  int offset) const = 0;
    virtual bool isOpSupported(operation, DataType) const = 0;
    virtual bool isAccessSupported(DataFile, DataType) const = 0;
    virtual bool isModSupported(const Instruction *,
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
index 014c652eede..a03afa8dc8d 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.cpp
@@ -384,6 +384,16 @@ TargetNVC0::insnCanLoad(const Instruction *i, int s,
 }
 
 bool
+TargetNVC0::insnCanLoadOffset(const Instruction *insn, int s, int offset) const
+{
+   const ValueRef& ref = insn->src(s);
+   if (ref.getFile() == FILE_MEMORY_CONST &&
+       (insn->op != OP_LOAD || insn->subOp != NV50_IR_SUBOP_LDC_IS))
+      return offset >= -0x8000 && offset < 0x8000;
+   return true;
+}
+
+bool
 TargetNVC0::isAccessSupported(DataFile file, DataType ty) const
 {
    if (ty == TYPE_NONE)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.h b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.h
index 3c5c7480405..7d11cd96315 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.h
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_target_nvc0.h
@@ -48,6 +48,8 @@ public:
 
    virtual bool insnCanLoad(const Instruction *insn, int s,
                             const Instruction *ld) const;
+   virtual bool insnCanLoadOffset(const Instruction *insn, int s,
+                                  int offset) const;
    virtual bool isOpSupported(operation, DataType) const;
    virtual bool isAccessSupported(DataFile, DataType) const;
    virtual bool isModSupported(const Instruction *, int s, Modifier) const;