glsl: Use a separate div_to_mul_rcp lowering flag for integers.

Using multiply and reciprocal for integer division involves potentially
lossy floating point conversions.  This is okay for older GPUs that
represent integers as floating point, but undesirable for GPUs with
native integer division instructions.

TGSI, for example, has UDIV/IDIV instructions for integer division,
so it makes sense to handle this directly.  Likewise for i965.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Bryan Cain <bryancain3@gmail.com>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Bryan Cain
2011-08-27 18:32:58 -05:00
committed by Kenneth Graunke
parent 87679e2ea1
commit 478034f34a
5 changed files with 79 additions and 62 deletions

View File

@@ -3232,7 +3232,7 @@ _mesa_ir_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
/* Lowering */
do_mat_op_to_vec(ir);
lower_instructions(ir, (MOD_TO_FRACT | DIV_TO_MUL_RCP | EXP_TO_EXP2
| LOG_TO_LOG2
| LOG_TO_LOG2 | INT_DIV_TO_MUL_RCP
| ((options->EmitNoPow) ? POW_TO_EXP2 : 0)));
progress = do_lower_jumps(ir, true, true, options->EmitNoMainReturn, options->EmitNoCont, options->EmitNoLoops) || progress;