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intel/vec4: Fix lowering of multiplication by 16-bit constant 

Existing code was ignoring whether the type of the immediate source
was signed or not.  If the source was signed, it would ignore small
negative values but it also would wrongly accept values between
INT16_MAX and UINT16_MAX, causing the atual value to later be
reinterpreted as a negative number (under 16-bits).

Fixes tests/shaders/glsl-mul-const.shader_test in Piglit for older
platforms that don't support MUL with 32x32 types and use vec4.

Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
This commit is contained in:
Caio Marcelo de Oliveira Filho 2019-12-16 14:43:53 -08:00
parent 2137be22fa
commit 766fdeccf9
1 changed files with 14 additions and 2 deletions
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16
src/intel/compiler/brw_vec4_nir.cpp
View File

@ -1109,6 +1109,18 @@ vec4_visitor::fix_float_operands(src_reg op[3], nir_alu_instr *instr)
}
}
static bool
const_src_fits_in_16_bits(const nir_src &src, brw_reg_type type)
{
assert(nir_src_is_const(src));
if (type_is_unsigned_int(type)) {
return nir_src_comp_as_uint(src, 0) <= UINT16_MAX;
} else {
const int64_t c = nir_src_comp_as_int(src, 0);
return c <= INT16_MAX && c >= INT16_MIN;
}
}
void
vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
{
@ -1217,14 +1229,14 @@ vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
*/
if (nir_src_is_const(instr->src[0].src) &&
nir_alu_instr_src_read_mask(instr, 0) == 1 &&
nir_src_comp_as_uint(instr->src[0].src, 0) < (1 << 16)) {
const_src_fits_in_16_bits(instr->src[0].src, op[0].type)) {
if (devinfo->gen < 7)
emit(MUL(dst, op[0], op[1]));
else
emit(MUL(dst, op[1], op[0]));
} else if (nir_src_is_const(instr->src[1].src) &&
nir_alu_instr_src_read_mask(instr, 1) == 1 &&
nir_src_comp_as_uint(instr->src[1].src, 0) < (1 << 16)) {
const_src_fits_in_16_bits(instr->src[1].src, op[1].type)) {
if (devinfo->gen < 7)
emit(MUL(dst, op[1], op[0]));
else