i965/fs: Properly handle sign(-abs(x))

Fixes new piglit tests:

 - glsl-1.10/execution/fs-sign-neg-abs.shader_test
 - glsl-1.10/execution/fs-sign-sat-neg-abs.shader_test
 - glsl-1.10/execution/vs-sign-neg-abs.shader_test
 - glsl-1.10/execution/vs-sign-sat-neg-abs.shader_test

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This commit is contained in:
Ian Romanick
2018-06-26 15:11:21 -07:00
parent c05c8d65ba
commit 88bd37c010

View File

@@ -834,11 +834,20 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
case nir_op_fsign: {
if (op[0].abs) {
/* Straightforward since the source can be assumed to be
* non-negative.
/* Straightforward since the source can be assumed to be either
* strictly >= 0 or strictly <= 0 depending on the setting of the
* negate flag.
*/
set_condmod(BRW_CONDITIONAL_NZ, bld.MOV(result, op[0]));
set_predicate(BRW_PREDICATE_NORMAL, bld.MOV(result, brw_imm_f(1.0f)));
inst = (op[0].negate)
? bld.MOV(result, brw_imm_f(-1.0f))
: bld.MOV(result, brw_imm_f(1.0f));
set_predicate(BRW_PREDICATE_NORMAL, inst);
if (instr->dest.saturate)
inst->saturate = true;
} else if (type_sz(op[0].type) < 8) {
/* AND(val, 0x80000000) gives the sign bit.