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

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: 5428066f5e1ef5ea6ae04c84019f270023cfc6aa
URL:    
http://cgit.freedesktop.org/mesa/mesa/commit/?id=5428066f5e1ef5ea6ae04c84019f270023cfc6aa

Author: Ilia Mirkin <imir...@alum.mit.edu>
Date:   Mon Apr  9 22:19:35 2018 -0400

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 <imir...@alum.mit.edu>

---

 src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp | 86 ++++++++++++----------
 1 file changed, 49 insertions(+), 37 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp 
b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
index 3953475c0a..28e0e260ce 100644
--- 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());
          }
       }
    }

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