[Mesa-dev] [PATCH 6/6] i965/fs: Remove fs_visitor::try_replace_with_sel().

[Matt Turner]

No shader-db changes on g4x, snb, hsw, or bdw.
---
opt_peephole_sel() still offers some small benefits.

 src/mesa/drivers/dri/i965/brw_fs.h           |  1 -
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp     |  2 -
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 89 ----------------------------
 3 files changed, 92 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 31f39fe..0a89d2e 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -225,7 +225,6 @@ public:
    void emit_gen6_gather_wa(uint8_t wa, fs_reg dst);
    fs_reg resolve_source_modifiers(const fs_reg &src);
    void emit_discard_jump();
-   bool try_replace_with_sel();
    bool opt_peephole_sel();
    bool opt_peephole_predicated_break();
    bool opt_saturate_propagation();
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 430efb3..ed3fe73 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -415,8 +415,6 @@ fs_visitor::nir_emit_if(nir_if *if_stmt)
    nir_emit_cf_list(&if_stmt->else_list);
 
    bld.emit(BRW_OPCODE_ENDIF);
-
-   try_replace_with_sel();
 }
 
 void
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 111db8c..504673f 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -441,95 +441,6 @@ fs_visitor::swizzle_result(ir_texture_opcode op, int dest_components,
    }
 }
 
-/**
- * Try to replace IF/MOV/ELSE/MOV/ENDIF with SEL.
- *
- * Many GLSL shaders contain the following pattern:
- *
- *    x = condition ? foo : bar
- *
- * The compiler emits an ir_if tree for this, since each subexpression might be
- * a complex tree that could have side-effects or short-circuit logic.
- *
- * However, the common case is to simply select one of two constants or
- * variable values---which is exactly what SEL is for.  In this case, the
- * assembly looks like:
- *
- *    (+f0) IF
- *    MOV dst src0
- *    ELSE
- *    MOV dst src1
- *    ENDIF
- *
- * which can be easily translated into:
- *
- *    (+f0) SEL dst src0 src1
- *
- * If src0 is an immediate value, we promote it to a temporary GRF.
- */
-bool
-fs_visitor::try_replace_with_sel()
-{
-   fs_inst *endif_inst = (fs_inst *) instructions.get_tail();
-   assert(endif_inst->opcode == BRW_OPCODE_ENDIF);
-
-   /* Pattern match in reverse: IF, MOV, ELSE, MOV, ENDIF. */
-   int opcodes[] = {
-      BRW_OPCODE_IF, BRW_OPCODE_MOV, BRW_OPCODE_ELSE, BRW_OPCODE_MOV,
-   };
-
-   fs_inst *match = (fs_inst *) endif_inst->prev;
-   for (int i = 0; i < 4; i++) {
-      if (match->is_head_sentinel() || match->opcode != opcodes[4-i-1])
-         return false;
-      match = (fs_inst *) match->prev;
-   }
-
-   /* The opcodes match; it looks like the right sequence of instructions. */
-   fs_inst *else_mov = (fs_inst *) endif_inst->prev;
-   fs_inst *then_mov = (fs_inst *) else_mov->prev->prev;
-   fs_inst *if_inst = (fs_inst *) then_mov->prev;
-
-   /* Check that the MOVs are the right form. */
-   if (then_mov->dst.equals(else_mov->dst) &&
-       !then_mov->is_partial_write() &&
-       !else_mov->is_partial_write()) {
-
-      /* Remove the matched instructions; we'll emit a SEL to replace them. */
-      while (!if_inst->next->is_tail_sentinel())
-         if_inst->next->exec_node::remove();
-      if_inst->exec_node::remove();
-
-      /* Only the last source register can be a constant, so if the MOV in
-       * the "then" clause uses a constant, we need to put it in a temporary.
-       */
-      fs_reg src0(then_mov->src[0]);
-      if (src0.file == IMM) {
-         src0 = vgrf(glsl_type::float_type);
-         src0.type = then_mov->src[0].type;
-         bld.MOV(src0, then_mov->src[0]);
-      }
-
-      if (if_inst->conditional_mod) {
-         /* Sandybridge-specific IF with embedded comparison */
-         bld.CMP(bld.null_reg_d(), if_inst->src[0], if_inst->src[1],
-                 if_inst->conditional_mod);
-         set_predicate(BRW_PREDICATE_NORMAL,
-                       bld.emit(BRW_OPCODE_SEL, then_mov->dst,
-                                src0, else_mov->src[0]));
-      } else {
-         /* Separate CMP and IF instructions */
-         set_predicate_inv(if_inst->predicate, if_inst->predicate_inverse,
-                           bld.emit(BRW_OPCODE_SEL, then_mov->dst,
-                                    src0, else_mov->src[0]));
-      }
-
-      return true;
-   }
-
-   return false;
-}
-
 /** Emits a dummy fragment shader consisting of magenta for bringup purposes. */
 void
 fs_visitor::emit_dummy_fs()
-- 
2.4.6