Mesa (master): i965/fs: Indent the implementation of 32x32-bit MUL lowering by one level.
Francisco Jerez
currojerez at kemper.freedesktop.org
Thu Aug 6 11:39:44 UTC 2015
Module: Mesa
Branch: master
Commit: 2e731264382954beb1192cd7cc62e16e0b8e7978
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=2e731264382954beb1192cd7cc62e16e0b8e7978
Author: Francisco Jerez <currojerez at riseup.net>
Date: Wed Aug 5 16:47:18 2015 +0300
i965/fs: Indent the implementation of 32x32-bit MUL lowering by one level.
In order to make room for the code that will lower the MULH virtual
instruction. Also move the hardware generation and execution type
checks into the same branch, they are going to have to be different
for MULH.
Reviewed-by: Matt Turner <mattst88 at gmail.com>
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 264 +++++++++++++++++-----------------
1 file changed, 134 insertions(+), 130 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 0278237..17f0eab 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3129,155 +3129,159 @@ fs_visitor::lower_integer_multiplication()
{
bool progress = false;
- /* Gen8's MUL instruction can do a 32-bit x 32-bit -> 32-bit operation
- * directly, but CHV/BXT cannot.
- */
- if (devinfo->gen >= 8 && !devinfo->is_cherryview && !devinfo->is_broxton)
- return false;
-
foreach_block_and_inst_safe(block, fs_inst, inst, cfg) {
- if (inst->opcode != BRW_OPCODE_MUL ||
- inst->dst.is_accumulator() ||
- (inst->dst.type != BRW_REGISTER_TYPE_D &&
- inst->dst.type != BRW_REGISTER_TYPE_UD))
- continue;
-
const fs_builder ibld(this, block, inst);
- /* 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.
- *
- * If multiplying by an immediate value that fits in 16-bits, do a
- * single MUL instruction with that value in the proper location.
- */
- if (inst->src[1].file == IMM &&
- inst->src[1].fixed_hw_reg.dw1.ud < (1 << 16)) {
- if (devinfo->gen < 7) {
- fs_reg imm(GRF, alloc.allocate(dispatch_width / 8),
- inst->dst.type);
- ibld.MOV(imm, inst->src[1]);
- ibld.MUL(inst->dst, imm, inst->src[0]);
- } else {
- ibld.MUL(inst->dst, inst->src[0], inst->src[1]);
- }
- } else {
- /* Gen < 8 (and some Gen8+ low-power parts like Cherryview) cannot
- * do 32-bit integer multiplication in one instruction, but instead
- * must do a sequence (which actually calculates a 64-bit result):
- *
- * mul(8) acc0<1>D g3<8,8,1>D g4<8,8,1>D
- * mach(8) null g3<8,8,1>D g4<8,8,1>D
- * mov(8) g2<1>D acc0<8,8,1>D
- *
- * But on Gen > 6, the ability to use second accumulator register
- * (acc1) for non-float data types was removed, preventing a simple
- * implementation in SIMD16. A 16-channel result can be calculated by
- * executing the three instructions twice in SIMD8, once with quarter
- * control of 1Q for the first eight channels and again with 2Q for
- * the second eight channels.
- *
- * Which accumulator register is implicitly accessed (by AccWrEnable
- * for instance) is determined by the quarter control. Unfortunately
- * Ivybridge (and presumably Baytrail) has a hardware bug in which an
- * implicit accumulator access by an instruction with 2Q will access
- * acc1 regardless of whether the data type is usable in acc1.
- *
- * Specifically, the 2Q mach(8) writes acc1 which does not exist for
- * integer data types.
- *
- * Since we only want the low 32-bits of the result, we can do two
- * 32-bit x 16-bit multiplies (like the mul and mach are doing), and
- * adjust the high result and add them (like the mach is doing):
- *
- * mul(8) g7<1>D g3<8,8,1>D g4.0<8,8,1>UW
- * mul(8) g8<1>D g3<8,8,1>D g4.1<8,8,1>UW
- * shl(8) g9<1>D g8<8,8,1>D 16D
- * add(8) g2<1>D g7<8,8,1>D g8<8,8,1>D
- *
- * We avoid the shl instruction by realizing that we only want to add
- * the low 16-bits of the "high" result to the high 16-bits of the
- * "low" result and using proper regioning on the add:
- *
- * mul(8) g7<1>D g3<8,8,1>D g4.0<16,8,2>UW
- * mul(8) g8<1>D g3<8,8,1>D g4.1<16,8,2>UW
- * add(8) g7.1<2>UW g7.1<16,8,2>UW g8<16,8,2>UW
- *
- * Since it does not use the (single) accumulator register, we can
- * schedule multi-component multiplications much better.
+ if (inst->opcode == BRW_OPCODE_MUL) {
+ if (inst->dst.is_accumulator() ||
+ (inst->dst.type != BRW_REGISTER_TYPE_D &&
+ inst->dst.type != BRW_REGISTER_TYPE_UD))
+ continue;
+
+ /* Gen8's MUL instruction can do a 32-bit x 32-bit -> 32-bit
+ * operation directly, but CHV/BXT cannot.
*/
+ if (devinfo->gen >= 8 &&
+ !devinfo->is_cherryview && !devinfo->is_broxton)
+ continue;
- if (inst->conditional_mod && inst->dst.is_null()) {
- inst->dst = fs_reg(GRF, alloc.allocate(dispatch_width / 8),
- inst->dst.type);
- }
- fs_reg low = inst->dst;
- fs_reg high(GRF, alloc.allocate(dispatch_width / 8),
- inst->dst.type);
+ if (inst->src[1].file == IMM &&
+ inst->src[1].fixed_hw_reg.dw1.ud < (1 << 16)) {
+ /* 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.
+ *
+ * If multiplying by an immediate value that fits in 16-bits, do a
+ * single MUL instruction with that value in the proper location.
+ */
+ if (devinfo->gen < 7) {
+ fs_reg imm(GRF, alloc.allocate(dispatch_width / 8),
+ inst->dst.type);
+ ibld.MOV(imm, inst->src[1]);
+ ibld.MUL(inst->dst, imm, inst->src[0]);
+ } else {
+ ibld.MUL(inst->dst, inst->src[0], inst->src[1]);
+ }
+ } else {
+ /* Gen < 8 (and some Gen8+ low-power parts like Cherryview) cannot
+ * do 32-bit integer multiplication in one instruction, but instead
+ * must do a sequence (which actually calculates a 64-bit result):
+ *
+ * mul(8) acc0<1>D g3<8,8,1>D g4<8,8,1>D
+ * mach(8) null g3<8,8,1>D g4<8,8,1>D
+ * mov(8) g2<1>D acc0<8,8,1>D
+ *
+ * But on Gen > 6, the ability to use second accumulator register
+ * (acc1) for non-float data types was removed, preventing a simple
+ * implementation in SIMD16. A 16-channel result can be calculated by
+ * executing the three instructions twice in SIMD8, once with quarter
+ * control of 1Q for the first eight channels and again with 2Q for
+ * the second eight channels.
+ *
+ * Which accumulator register is implicitly accessed (by AccWrEnable
+ * for instance) is determined by the quarter control. Unfortunately
+ * Ivybridge (and presumably Baytrail) has a hardware bug in which an
+ * implicit accumulator access by an instruction with 2Q will access
+ * acc1 regardless of whether the data type is usable in acc1.
+ *
+ * Specifically, the 2Q mach(8) writes acc1 which does not exist for
+ * integer data types.
+ *
+ * Since we only want the low 32-bits of the result, we can do two
+ * 32-bit x 16-bit multiplies (like the mul and mach are doing), and
+ * adjust the high result and add them (like the mach is doing):
+ *
+ * mul(8) g7<1>D g3<8,8,1>D g4.0<8,8,1>UW
+ * mul(8) g8<1>D g3<8,8,1>D g4.1<8,8,1>UW
+ * shl(8) g9<1>D g8<8,8,1>D 16D
+ * add(8) g2<1>D g7<8,8,1>D g8<8,8,1>D
+ *
+ * We avoid the shl instruction by realizing that we only want to add
+ * the low 16-bits of the "high" result to the high 16-bits of the
+ * "low" result and using proper regioning on the add:
+ *
+ * mul(8) g7<1>D g3<8,8,1>D g4.0<16,8,2>UW
+ * mul(8) g8<1>D g3<8,8,1>D g4.1<16,8,2>UW
+ * add(8) g7.1<2>UW g7.1<16,8,2>UW g8<16,8,2>UW
+ *
+ * Since it does not use the (single) accumulator register, we can
+ * schedule multi-component multiplications much better.
+ */
- if (devinfo->gen >= 7) {
- fs_reg src1_0_w = inst->src[1];
- fs_reg src1_1_w = inst->src[1];
+ if (inst->conditional_mod && inst->dst.is_null()) {
+ inst->dst = fs_reg(GRF, alloc.allocate(dispatch_width / 8),
+ inst->dst.type);
+ }
+ fs_reg low = inst->dst;
+ fs_reg high(GRF, alloc.allocate(dispatch_width / 8),
+ inst->dst.type);
- if (inst->src[1].file == IMM) {
- src1_0_w.fixed_hw_reg.dw1.ud &= 0xffff;
- src1_1_w.fixed_hw_reg.dw1.ud >>= 16;
- } else {
- src1_0_w.type = BRW_REGISTER_TYPE_UW;
- if (src1_0_w.stride != 0) {
- assert(src1_0_w.stride == 1);
- src1_0_w.stride = 2;
+ if (devinfo->gen >= 7) {
+ fs_reg src1_0_w = inst->src[1];
+ fs_reg src1_1_w = inst->src[1];
+
+ if (inst->src[1].file == IMM) {
+ src1_0_w.fixed_hw_reg.dw1.ud &= 0xffff;
+ src1_1_w.fixed_hw_reg.dw1.ud >>= 16;
+ } else {
+ src1_0_w.type = BRW_REGISTER_TYPE_UW;
+ if (src1_0_w.stride != 0) {
+ assert(src1_0_w.stride == 1);
+ src1_0_w.stride = 2;
+ }
+
+ src1_1_w.type = BRW_REGISTER_TYPE_UW;
+ if (src1_1_w.stride != 0) {
+ assert(src1_1_w.stride == 1);
+ src1_1_w.stride = 2;
+ }
+ src1_1_w.subreg_offset += type_sz(BRW_REGISTER_TYPE_UW);
}
+ ibld.MUL(low, inst->src[0], src1_0_w);
+ ibld.MUL(high, inst->src[0], src1_1_w);
+ } else {
+ fs_reg src0_0_w = inst->src[0];
+ fs_reg src0_1_w = inst->src[0];
- src1_1_w.type = BRW_REGISTER_TYPE_UW;
- if (src1_1_w.stride != 0) {
- assert(src1_1_w.stride == 1);
- src1_1_w.stride = 2;
+ src0_0_w.type = BRW_REGISTER_TYPE_UW;
+ if (src0_0_w.stride != 0) {
+ assert(src0_0_w.stride == 1);
+ src0_0_w.stride = 2;
}
- src1_1_w.subreg_offset += type_sz(BRW_REGISTER_TYPE_UW);
- }
- ibld.MUL(low, inst->src[0], src1_0_w);
- ibld.MUL(high, inst->src[0], src1_1_w);
- } else {
- fs_reg src0_0_w = inst->src[0];
- fs_reg src0_1_w = inst->src[0];
- src0_0_w.type = BRW_REGISTER_TYPE_UW;
- if (src0_0_w.stride != 0) {
- assert(src0_0_w.stride == 1);
- src0_0_w.stride = 2;
- }
+ src0_1_w.type = BRW_REGISTER_TYPE_UW;
+ if (src0_1_w.stride != 0) {
+ assert(src0_1_w.stride == 1);
+ src0_1_w.stride = 2;
+ }
+ src0_1_w.subreg_offset += type_sz(BRW_REGISTER_TYPE_UW);
- src0_1_w.type = BRW_REGISTER_TYPE_UW;
- if (src0_1_w.stride != 0) {
- assert(src0_1_w.stride == 1);
- src0_1_w.stride = 2;
+ ibld.MUL(low, src0_0_w, inst->src[1]);
+ ibld.MUL(high, src0_1_w, inst->src[1]);
}
- src0_1_w.subreg_offset += type_sz(BRW_REGISTER_TYPE_UW);
- ibld.MUL(low, src0_0_w, inst->src[1]);
- ibld.MUL(high, src0_1_w, inst->src[1]);
- }
-
- fs_reg dst = inst->dst;
- dst.type = BRW_REGISTER_TYPE_UW;
- dst.subreg_offset = 2;
- dst.stride = 2;
+ fs_reg dst = inst->dst;
+ dst.type = BRW_REGISTER_TYPE_UW;
+ dst.subreg_offset = 2;
+ dst.stride = 2;
- high.type = BRW_REGISTER_TYPE_UW;
- high.stride = 2;
+ high.type = BRW_REGISTER_TYPE_UW;
+ high.stride = 2;
- low.type = BRW_REGISTER_TYPE_UW;
- low.subreg_offset = 2;
- low.stride = 2;
+ low.type = BRW_REGISTER_TYPE_UW;
+ low.subreg_offset = 2;
+ low.stride = 2;
- ibld.ADD(dst, low, high);
+ ibld.ADD(dst, low, high);
- if (inst->conditional_mod) {
- fs_reg null(retype(ibld.null_reg_f(), inst->dst.type));
- set_condmod(inst->conditional_mod,
- ibld.MOV(null, inst->dst));
+ if (inst->conditional_mod) {
+ fs_reg null(retype(ibld.null_reg_f(), inst->dst.type));
+ set_condmod(inst->conditional_mod,
+ ibld.MOV(null, inst->dst));
+ }
}
+ } else {
+ continue;
}
inst->remove(block);
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