nv50/ir: make a copy of tex src if it's referenced multiple times

For nv50 we coalesce the srcs and defs into a single node. As such, we
can end up with impossible constraints if the source is referenced
after the tex operation (which, due to the coalescing of values, will
have overwritten it).

This logic already exists for inserting moves for MERGE/UNION sources.
It's the exact same idea here, so leverage that code, which also
includes a few optimizations around not extending live ranges
unnecessarily.

Fixes tests/spec/glsl-1.30/execution/fs-textureSize-components.shader_test

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

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
index 3953475c0ac7c210d2456715823f02bc62b3fa2b..28e0e260cee79111cfa282b10e52ef69ace0b1bc 100644 (file)
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
@@ -257,6 +257,7 @@ private:
    private:
       virtual bool visit(BasicBlock *);
 
+      void insertConstraintMove(Instruction *, int s);
       bool insertConstraintMoves();
 
       void condenseDefs(Instruction *);
@@ -2235,6 +2236,8 @@ RegAlloc::InsertConstraintsPass::texConstraintNV50(TexInstruction *tex)
    for (c = 0; tex->srcExists(c) || tex->defExists(c); ++c) {
       if (!tex->srcExists(c))
          tex->setSrc(c, new_LValue(func, tex->getSrc(0)->asLValue()));
+      else
+         insertConstraintMove(tex, c);
       if (!tex->defExists(c))
          tex->setDef(c, new_LValue(func, tex->getDef(0)->asLValue()));
    }
@@ -2307,6 +2310,51 @@ RegAlloc::InsertConstraintsPass::visit(BasicBlock *bb)
    return true;
 }
 
+void
+RegAlloc::InsertConstraintsPass::insertConstraintMove(Instruction *cst, int s)
+{
+   const uint8_t size = cst->src(s).getSize();
+
+   assert(cst->getSrc(s)->defs.size() == 1); // still SSA
+
+   Instruction *defi = cst->getSrc(s)->defs.front()->getInsn();
+   bool imm = defi->op == OP_MOV &&
+      defi->src(0).getFile() == FILE_IMMEDIATE;
+   bool load = defi->op == OP_LOAD &&
+      defi->src(0).getFile() == FILE_MEMORY_CONST &&
+      !defi->src(0).isIndirect(0);
+   // catch some cases where don't really need MOVs
+   if (cst->getSrc(s)->refCount() == 1 && !defi->constrainedDefs()) {
+      if (imm || load) {
+         // Move the defi right before the cst. No point in expanding
+         // the range.
+         defi->bb->remove(defi);
+         cst->bb->insertBefore(cst, defi);
+      }
+      return;
+   }
+
+   LValue *lval = new_LValue(func, cst->src(s).getFile());
+   lval->reg.size = size;
+
+   Instruction *mov = new_Instruction(func, OP_MOV, typeOfSize(size));
+   mov->setDef(0, lval);
+   mov->setSrc(0, cst->getSrc(s));
+
+   if (load) {
+      mov->op = OP_LOAD;
+      mov->setSrc(0, defi->getSrc(0));
+   } else if (imm) {
+      mov->setSrc(0, defi->getSrc(0));
+   }
+
+   if (defi->getPredicate())
+      mov->setPredicate(defi->cc, defi->getPredicate());
+
+   cst->setSrc(s, mov->getDef(0));
+   cst->bb->insertBefore(cst, mov);
+}
+
 // Insert extra moves so that, if multiple register constraints on a value are
 // in conflict, these conflicts can be resolved.
 bool
@@ -2347,46 +2395,10 @@ RegAlloc::InsertConstraintsPass::insertConstraintMoves()
                cst->bb->insertBefore(cst, mov);
                continue;
             }
-            assert(cst->getSrc(s)->defs.size() == 1); // still SSA
-
-            Instruction *defi = cst->getSrc(s)->defs.front()->getInsn();
-            bool imm = defi->op == OP_MOV &&
-               defi->src(0).getFile() == FILE_IMMEDIATE;
-            bool load = defi->op == OP_LOAD &&
-               defi->src(0).getFile() == FILE_MEMORY_CONST &&
-               !defi->src(0).isIndirect(0);
-            // catch some cases where don't really need MOVs
-            if (cst->getSrc(s)->refCount() == 1 && !defi->constrainedDefs()) {
-               if (imm || load) {
-                  // Move the defi right before the cst. No point in expanding
-                  // the range.
-                  defi->bb->remove(defi);
-                  cst->bb->insertBefore(cst, defi);
-               }
-               continue;
-            }
 
-            LValue *lval = new_LValue(func, cst->src(s).getFile());
-            lval->reg.size = size;
-
-            mov = new_Instruction(func, OP_MOV, typeOfSize(size));
-            mov->setDef(0, lval);
-            mov->setSrc(0, cst->getSrc(s));
-
-            if (load) {
-               mov->op = OP_LOAD;
-               mov->setSrc(0, defi->getSrc(0));
-            } else if (imm) {
-               mov->setSrc(0, defi->getSrc(0));
-            }
-
-            cst->setSrc(s, mov->getDef(0));
-            cst->bb->insertBefore(cst, mov);
+            insertConstraintMove(cst, s);
 
             cst->getDef(0)->asLValue()->noSpill = 1; // doesn't help
-
-            if (cst->op == OP_UNION)
-               mov->setPredicate(defi->cc, defi->getPredicate());
          }
       }
    }