From 2137be22fa2c75eda462456f2b7778684d0631fc Mon Sep 17 00:00:00 2001 From: Caio Marcelo de Oliveira Filho Date: Mon, 16 Dec 2019 13:37:41 -0800 Subject: [PATCH] intel/fs: Fix lowering of dword 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 platforms that don't support MUL with 32x32 types, including ICL and TGL. Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2186 Cc: Reviewed-by: Jason Ekstrand --- src/intel/compiler/brw_fs.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp index a01b01048c8..beeac84e43d 100644 --- a/src/intel/compiler/brw_fs.cpp +++ b/src/intel/compiler/brw_fs.cpp @@ -3908,7 +3908,10 @@ fs_visitor::lower_mul_dword_inst(fs_inst *inst, bblock_t *block) { const fs_builder ibld(this, block, inst); - if (inst->src[1].file == IMM && inst->src[1].ud < (1 << 16)) { + const bool ud = (inst->src[1].type == BRW_REGISTER_TYPE_UD); + if (inst->src[1].file == IMM && + (( ud && inst->src[1].ud <= UINT16_MAX) || + (!ud && inst->src[1].d <= INT16_MAX && inst->src[1].d >= INT16_MIN))) { /* The MUL instruction isn't commutative. On Gen <= 6, only the low * 16-bits of src0 are read, and on Gen >= 7 only the low 16-bits of * src1 are used. @@ -3921,7 +3924,6 @@ fs_visitor::lower_mul_dword_inst(fs_inst *inst, bblock_t *block) ibld.MOV(imm, inst->src[1]); ibld.MUL(inst->dst, imm, inst->src[0]); } else { - const bool ud = (inst->src[1].type == BRW_REGISTER_TYPE_UD); ibld.MUL(inst->dst, inst->src[0], ud ? brw_imm_uw(inst->src[1].ud) : brw_imm_w(inst->src[1].d)); -- 2.30.2