[Mesa-dev] [PATCH 8/8] i965: Only iterate over the actual number of source registers

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

Itrating over all 3 possible source registers regardless of the opcode
was causing a variety of problems.  The most noticable was an
occasional assertion failure:

brw_vs_emit.c:1381: get_src_reg: Assertion `c->regs[file][index].nr !=
0' failed.

This assertion seemed to be triggered by reading from an uniform
array-of-matrix using multiple non-constant indices.

Fixes i965 piglit:

    vs-uniform-array-mat[234]-col-row-rd
    vs-uniform-array-mat[234]-index-col-row-rd
    vs-uniform-array-mat[234]-index-row-rd
    vs-uniform-mat[234]-col-row-rd
---
 src/mesa/drivers/dri/i965/brw_vs_emit.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_vs_emit.c b/src/mesa/drivers/dri/i965/brw_vs_emit.c
index 9d73334..3949382 100644
--- a/src/mesa/drivers/dri/i965/brw_vs_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_vs_emit.c
@@ -220,8 +220,9 @@ static void brw_vs_alloc_regs( struct brw_vs_compile *c )
 	i++) {
       struct prog_instruction *inst = &c->vp->program.Base.Instructions[i];
       int arg;
+      const unsigned num_src = _mesa_num_inst_src_regs(inst->Opcode);
 
-      for (arg = 0; arg < 3 && constant < max_constant; arg++) {
+      for (arg = 0; arg < num_src && constant < max_constant; arg++) {
 	 if (inst->SrcReg[arg].File != PROGRAM_STATE_VAR &&
 	     inst->SrcReg[arg].File != PROGRAM_CONSTANT &&
 	     inst->SrcReg[arg].File != PROGRAM_UNIFORM &&
@@ -1931,11 +1932,12 @@ void brw_vs_emit(struct brw_vs_compile *c )
    for (insn = 0; insn < nr_insns; insn++) {
        GLuint i;
        struct prog_instruction *inst = &c->vp->program.Base.Instructions[insn];
+       const unsigned num_src = _mesa_num_inst_src_regs(inst->Opcode);
 
        /* Message registers can't be read, so copy the output into GRF
 	* register if they are used in source registers
 	*/
-       for (i = 0; i < 3; i++) {
+       for (i = 0; i < num_src; i++) {
 	   struct prog_src_register *src = &inst->SrcReg[i];
 	   GLuint index = src->Index;
 	   GLuint file = src->File;	
@@ -1975,8 +1977,9 @@ void brw_vs_emit(struct brw_vs_compile *c )
 
       /* Get argument regs.  SWZ is special and does this itself.
        */
-      if (inst->Opcode != OPCODE_SWZ)
-	  for (i = 0; i < 3; i++) {
+      if (inst->Opcode != OPCODE_SWZ) {
+	  const unsigned num_src = _mesa_num_inst_src_regs(inst->Opcode);
+	  for (i = 0; i < num_src; i++) {
 	      const struct prog_src_register *src = &inst->SrcReg[i];
 	      index = src->Index;
 	      file = src->File;	
@@ -1985,6 +1988,7 @@ void brw_vs_emit(struct brw_vs_compile *c )
 	      else
                   args[i] = get_arg(c, inst, i);
 	  }
+      }
 
       /* Get dest regs.  Note that it is possible for a reg to be both
        * dst and arg, given the static allocation of registers.  So
-- 
1.7.4.4