nir/range-analysis: Range tracking for ffma and flrp

A similar technique could be used for fmin3, fmax3, and fmid3.

This could be squashed with the previous commit.  I kept it separate to
ease review.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This commit is contained in:
Ian Romanick
2019-08-01 11:51:36 -07:00
parent 586602c5d9
commit fa116ce357

View File

@@ -232,6 +232,99 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
struct ssa_result_range r = {unknown, false};
/* ge_zero: ge_zero + ge_zero
*
* gt_zero: gt_zero + eq_zero
* | gt_zero + ge_zero
* | eq_zero + gt_zero # Addition is commutative
* | ge_zero + gt_zero # Addition is commutative
* | gt_zero + gt_zero
* ;
*
* le_zero: le_zero + le_zero
*
* lt_zero: lt_zero + eq_zero
* | lt_zero + le_zero
* | eq_zero + lt_zero # Addition is commutative
* | le_zero + lt_zero # Addition is commutative
* | lt_zero + lt_zero
* ;
*
* eq_zero: eq_zero + eq_zero
*
* All other cases are 'unknown'.
*/
static const enum ssa_ranges fadd_table[last_range + 1][last_range + 1] = {
/* left\right unknown lt_zero le_zero gt_zero ge_zero ne_zero eq_zero */
/* unknown */ { _______, _______, _______, _______, _______, _______, _______ },
/* lt_zero */ { _______, lt_zero, lt_zero, _______, _______, _______, lt_zero },
/* le_zero */ { _______, lt_zero, le_zero, _______, _______, _______, le_zero },
/* gt_zero */ { _______, _______, _______, gt_zero, gt_zero, _______, gt_zero },
/* ge_zero */ { _______, _______, _______, gt_zero, ge_zero, _______, ge_zero },
/* ne_zero */ { _______, _______, _______, _______, _______, ne_zero, ne_zero },
/* eq_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
};
ASSERT_TABLE_IS_COMMUTATIVE(fadd_table);
ASSERT_TABLE_IS_DIAGONAL(fadd_table);
/* ge_zero: ge_zero * ge_zero
* | ge_zero * gt_zero
* | ge_zero * eq_zero
* | le_zero * lt_zero
* | lt_zero * le_zero # Multiplication is commutative
* | le_zero * le_zero
* | gt_zero * ge_zero # Multiplication is commutative
* | eq_zero * ge_zero # Multiplication is commutative
* | a * a # Left source == right source
* ;
*
* gt_zero: gt_zero * gt_zero
* | lt_zero * lt_zero
* ;
*
* le_zero: ge_zero * le_zero
* | ge_zero * lt_zero
* | lt_zero * ge_zero # Multiplication is commutative
* | le_zero * ge_zero # Multiplication is commutative
* | le_zero * gt_zero
* ;
*
* lt_zero: lt_zero * gt_zero
* | gt_zero * lt_zero # Multiplication is commutative
* ;
*
* ne_zero: ne_zero * gt_zero
* | ne_zero * lt_zero
* | gt_zero * ne_zero # Multiplication is commutative
* | lt_zero * ne_zero # Multiplication is commutative
* | ne_zero * ne_zero
* ;
*
* eq_zero: eq_zero * <any>
* <any> * eq_zero # Multiplication is commutative
*
* All other cases are 'unknown'.
*/
static const enum ssa_ranges fmul_table[last_range + 1][last_range + 1] = {
/* left\right unknown lt_zero le_zero gt_zero ge_zero ne_zero eq_zero */
/* unknown */ { _______, _______, _______, _______, _______, _______, eq_zero },
/* lt_zero */ { _______, gt_zero, ge_zero, lt_zero, le_zero, ne_zero, eq_zero },
/* le_zero */ { _______, ge_zero, ge_zero, le_zero, le_zero, _______, eq_zero },
/* gt_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
/* ge_zero */ { _______, le_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
/* ne_zero */ { _______, ne_zero, _______, ne_zero, _______, ne_zero, eq_zero },
/* eq_zero */ { eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero }
};
ASSERT_TABLE_IS_COMMUTATIVE(fmul_table);
static const enum ssa_ranges fneg_table[last_range + 1] = {
/* unknown lt_zero le_zero gt_zero ge_zero ne_zero eq_zero */
_______, gt_zero, ge_zero, lt_zero, le_zero, ne_zero, eq_zero
};
switch (alu->op) {
case nir_op_b2f32:
case nir_op_b2i32:
@@ -353,44 +446,7 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
const struct ssa_result_range right = analyze_expression(alu, 1, ht);
r.is_integral = left.is_integral && right.is_integral;
/* ge_zero: ge_zero + ge_zero
*
* gt_zero: gt_zero + eq_zero
* | gt_zero + ge_zero
* | eq_zero + gt_zero # Addition is commutative
* | ge_zero + gt_zero # Addition is commutative
* | gt_zero + gt_zero
* ;
*
* le_zero: le_zero + le_zero
*
* lt_zero: lt_zero + eq_zero
* | lt_zero + le_zero
* | eq_zero + lt_zero # Addition is commutative
* | le_zero + lt_zero # Addition is commutative
* | lt_zero + lt_zero
* ;
*
* eq_zero: eq_zero + eq_zero
*
* All other cases are 'unknown'.
*/
static const enum ssa_ranges table[last_range + 1][last_range + 1] = {
/* left\right unknown lt_zero le_zero gt_zero ge_zero ne_zero eq_zero */
/* unknown */ { _______, _______, _______, _______, _______, _______, _______ },
/* lt_zero */ { _______, lt_zero, lt_zero, _______, _______, _______, lt_zero },
/* le_zero */ { _______, lt_zero, le_zero, _______, _______, _______, le_zero },
/* gt_zero */ { _______, _______, _______, gt_zero, gt_zero, _______, gt_zero },
/* ge_zero */ { _______, _______, _______, gt_zero, ge_zero, _______, ge_zero },
/* ne_zero */ { _______, _______, _______, _______, _______, ne_zero, ne_zero },
/* eq_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
};
ASSERT_TABLE_IS_COMMUTATIVE(table);
ASSERT_TABLE_IS_DIAGONAL(table);
r.range = table[left.range][right.range];
r.range = fadd_table[left.range][right.range];
break;
}
@@ -528,57 +584,6 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
r.is_integral = left.is_integral && right.is_integral;
/* ge_zero: ge_zero * ge_zero
* | ge_zero * gt_zero
* | ge_zero * eq_zero
* | le_zero * lt_zero
* | lt_zero * le_zero # Multiplication is commutative
* | le_zero * le_zero
* | gt_zero * ge_zero # Multiplication is commutative
* | eq_zero * ge_zero # Multiplication is commutative
* | a * a # Left source == right source
* ;
*
* gt_zero: gt_zero * gt_zero
* | lt_zero * lt_zero
* ;
*
* le_zero: ge_zero * le_zero
* | ge_zero * lt_zero
* | lt_zero * ge_zero # Multiplication is commutative
* | le_zero * ge_zero # Multiplication is commutative
* | le_zero * gt_zero
* ;
*
* lt_zero: lt_zero * gt_zero
* | gt_zero * lt_zero # Multiplication is commutative
* ;
*
* ne_zero: ne_zero * gt_zero
* | ne_zero * lt_zero
* | gt_zero * ne_zero # Multiplication is commutative
* | lt_zero * ne_zero # Multiplication is commutative
* | ne_zero * ne_zero
* ;
*
* eq_zero: eq_zero * <any>
* <any> * eq_zero # Multiplication is commutative
*
* All other cases are 'unknown'.
*/
static const enum ssa_ranges table[last_range + 1][last_range + 1] = {
/* left\right unknown lt_zero le_zero gt_zero ge_zero ne_zero eq_zero */
/* unknown */ { _______, _______, _______, _______, _______, _______, eq_zero },
/* lt_zero */ { _______, gt_zero, ge_zero, lt_zero, le_zero, ne_zero, eq_zero },
/* le_zero */ { _______, ge_zero, ge_zero, le_zero, le_zero, _______, eq_zero },
/* gt_zero */ { _______, lt_zero, le_zero, gt_zero, ge_zero, ne_zero, eq_zero },
/* ge_zero */ { _______, le_zero, le_zero, ge_zero, ge_zero, _______, eq_zero },
/* ne_zero */ { _______, ne_zero, _______, ne_zero, _______, ne_zero, eq_zero },
/* eq_zero */ { eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero, eq_zero }
};
ASSERT_TABLE_IS_COMMUTATIVE(table);
/* x * x => ge_zero */
if (left.range != eq_zero && nir_alu_srcs_equal(alu, alu, 0, 1)) {
/* x * x => ge_zero or gt_zero depending on the range of x. */
@@ -587,7 +592,7 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
/* -x * x => le_zero or lt_zero depending on the range of x. */
r.range = is_not_zero(left.range) ? lt_zero : le_zero;
} else
r.range = table[left.range][right.range];
r.range = fmul_table[left.range][right.range];
break;
}
@@ -603,30 +608,7 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
case nir_op_fneg:
r = analyze_expression(alu, 0, ht);
switch (r.range) {
case le_zero:
r.range = ge_zero;
break;
case ge_zero:
r.range = le_zero;
break;
case lt_zero:
r.range = gt_zero;
break;
case gt_zero:
r.range = lt_zero;
break;
case ne_zero:
case eq_zero:
case unknown:
/* Negation doesn't change anything about these ranges. */
break;
}
r.range = fneg_table[r.range];
break;
case nir_op_fsat:
@@ -724,6 +706,48 @@ analyze_expression(const nir_alu_instr *instr, unsigned src,
r = (struct ssa_result_range){le_zero, false};
break;
case nir_op_ffma: {
const struct ssa_result_range first = analyze_expression(alu, 0, ht);
const struct ssa_result_range second = analyze_expression(alu, 1, ht);
const struct ssa_result_range third = analyze_expression(alu, 2, ht);
r.is_integral = first.is_integral && second.is_integral &&
third.is_integral;
enum ssa_ranges fmul_range;
if (first.range != eq_zero && nir_alu_srcs_equal(alu, alu, 0, 1)) {
/* x * x => ge_zero or gt_zero depending on the range of x. */
fmul_range = is_not_zero(first.range) ? gt_zero : ge_zero;
} else if (first.range != eq_zero && nir_alu_srcs_negative_equal(alu, alu, 0, 1)) {
/* -x * x => le_zero or lt_zero depending on the range of x. */
fmul_range = is_not_zero(first.range) ? lt_zero : le_zero;
} else
fmul_range = fmul_table[first.range][second.range];
r.range = fadd_table[fmul_range][third.range];
break;
}
case nir_op_flrp: {
const struct ssa_result_range first = analyze_expression(alu, 0, ht);
const struct ssa_result_range second = analyze_expression(alu, 1, ht);
const struct ssa_result_range third = analyze_expression(alu, 2, ht);
r.is_integral = first.is_integral && second.is_integral &&
third.is_integral;
/* Decompose the flrp to first + third * (second + -first) */
const enum ssa_ranges inner_fadd_range =
fadd_table[second.range][fneg_table[first.range]];
const enum ssa_ranges fmul_range =
fmul_table[third.range][inner_fadd_range];
r.range = fadd_table[first.range][fmul_range];
break;
}
default:
r = (struct ssa_result_range){unknown, false};
break;