procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

openmp: Adjust outer bounds of non-rect loops

Browse source 
In loops like:
  #pragma omp parallel for collapse(2)
  for (i = -4; i < 8; i++)
    for (j = 3 * i; j > 2 * i; j--)
for some outer loop iterations there are no inner loop iterations at all,
the condition is false.  In order to use Summæ Potestate to count number
of iterations or to transform the logical iteration number to actual
iterator values using quadratic non-equation root discovery the outer
iterator range needs to be adjusted, such that the inner loop has at least
one iteration for each of the outer loop iterator value in the reduced
range.  Sometimes this adjustment is done at the start of the range,
at other times at the end.

This patch implements it during the compile time number of loop computation
(if all expressions are compile time constants).

2020-07-14  Jakub Jelinek  <jakub@redhat.com>

	* omp-general.h (struct omp_for_data): Add adjn1 member.
	* omp-general.c (omp_extract_for_data): For non-rect loop, punt on
	count computing if n1, n2 or step are not INTEGER_CST earlier.
	Narrow the outer iterator range if needed so that non-rect loop
	has at least one iteration for each outer range iteration.  Compute
	adjn1.
	* omp-expand.c (expand_omp_for_init_vars): Use adjn1 if non-NULL
	instead of the outer loop's n1.

	* testsuite/libgomp.c/loop-21.c: New test.
This commit is contained in:
Jakub Jelinek 2020-07-14 10:31:59 +02:00
parent 6a48d12475
commit f418bd4b92
4 changed files with 360 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
gcc/omp-expand.c
View file

@ -2262,6 +2262,7 @@ expand_omp_for_init_vars (struct omp_for_data *fd, gimple_stmt_iterator *gsi,
&& (optab_handler (sqrt_optab, TYPE_MODE (double_type_node))
!= CODE_FOR_nothing))
{
tree outer_n1 = fd->adjn1 ? fd->adjn1 : fd->loops[i - 1].n1;
tree itype = TREE_TYPE (fd->loops[i].v);
tree min_inner_iterations = fd->min_inner_iterations;
tree factor = fd->factor;
@ -2384,7 +2385,7 @@ expand_omp_for_init_vars (struct omp_for_data *fd, gimple_stmt_iterator *gsi,
*gsi = gsi_after_labels (e->dest);
t = fold_convert (itype, c);
t = fold_build2 (MULT_EXPR, itype, t, fd->loops[i - 1].step);
t = fold_build2 (PLUS_EXPR, itype, fd->loops[i - 1].n1, t);
t = fold_build2 (PLUS_EXPR, itype, outer_n1, t);
t = force_gimple_operand_gsi (gsi, t, true, NULL_TREE, false,
GSI_CONTINUE_LINKING);
expand_omp_build_assign (gsi, fd->loops[i - 1].v, t, true);

129
gcc/omp-general.c
View file

@ -214,6 +214,7 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
fd->simd_schedule = false;
fd->min_inner_iterations = NULL_TREE;
fd->factor = NULL_TREE;
fd->adjn1 = NULL_TREE;
collapse_iter = NULL;
collapse_count = NULL;
@ -508,7 +509,10 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
continue;
if (single_nonrect == -1
|| (loop->m1 && TREE_CODE (loop->m1) != INTEGER_CST)
|| (loop->m2 && TREE_CODE (loop->m2) != INTEGER_CST))
|| (loop->m2 && TREE_CODE (loop->m2) != INTEGER_CST)
|| TREE_CODE (loop->n1) != INTEGER_CST
|| TREE_CODE (loop->n2) != INTEGER_CST
|| TREE_CODE (loop->step) != INTEGER_CST)
{
count = NULL_TREE;
continue;
@ -574,12 +578,129 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
else if (t && t2 && integer_zerop (t) && integer_zerop (t2))
/* No iterations of the inner loop. count will be set to
zero cst below. */;
else
else if (TYPE_UNSIGNED (itype)
|| t == NULL_TREE
|| t2 == NULL_TREE
|| TREE_CODE (t) != INTEGER_CST
|| TREE_CODE (t2) != INTEGER_CST)
{
/* Punt (for now). */
count = NULL_TREE;
continue;
}
else
{
/* Some iterations of the outer loop have zero iterations
of the inner loop, while others have at least one.
In this case, we need to adjust one of those outer
loop bounds. If ADJ_FIRST, we need to adjust outer n1
(first), otherwise outer n2 (last). */
bool adj_first = integer_zerop (t);
tree n1 = fold_convert (itype, loop->n1);
tree n2 = fold_convert (itype, loop->n2);
tree m1 = loop->m1 ? fold_convert (itype, loop->m1)
: build_zero_cst (itype);
tree m2 = loop->m2 ? fold_convert (itype, loop->m2)
: build_zero_cst (itype);
t = fold_binary (MINUS_EXPR, itype, n1, n2);
t2 = fold_binary (MINUS_EXPR, itype, m2, m1);
t = fold_binary (TRUNC_DIV_EXPR, itype, t, t2);
t2 = fold_binary (MINUS_EXPR, itype, t, first);
t2 = fold_binary (TRUNC_MOD_EXPR, itype, t2, ostep);
t = fold_binary (MINUS_EXPR, itype, t, t2);
tree n1cur
= fold_binary (PLUS_EXPR, itype, n1,
fold_binary (MULT_EXPR, itype, m1, t));
tree n2cur
= fold_binary (PLUS_EXPR, itype, n2,
fold_binary (MULT_EXPR, itype, m2, t));
t2 = fold_binary (loop->cond_code, boolean_type_node,
n1cur, n2cur);
tree t3 = fold_binary (MULT_EXPR, itype, m1, ostep);
tree t4 = fold_binary (MULT_EXPR, itype, m2, ostep);
tree diff;
if (adj_first)
{
tree new_first;
if (integer_nonzerop (t2))
{
new_first = t;
n1first = n1cur;
n2first = n2cur;
if (flag_checking)
{
t3 = fold_binary (MINUS_EXPR, itype, n1cur, t3);
t4 = fold_binary (MINUS_EXPR, itype, n2cur, t4);
t3 = fold_binary (loop->cond_code,
boolean_type_node, t3, t4);
gcc_assert (integer_zerop (t3));
}
}
else
{
t3 = fold_binary (PLUS_EXPR, itype, n1cur, t3);
t4 = fold_binary (PLUS_EXPR, itype, n2cur, t4);
new_first = fold_binary (PLUS_EXPR, itype, t, ostep);
n1first = t3;
n2first = t4;
if (flag_checking)
{
t3 = fold_binary (loop->cond_code,
boolean_type_node, t3, t4);
gcc_assert (integer_nonzerop (t3));
}
}
diff = fold_binary (MINUS_EXPR, itype, new_first, first);
first = new_first;
fd->adjn1 = first;
}
else
{
tree new_last;
if (integer_zerop (t2))
{
t3 = fold_binary (MINUS_EXPR, itype, n1cur, t3);
t4 = fold_binary (MINUS_EXPR, itype, n2cur, t4);
new_last = fold_binary (MINUS_EXPR, itype, t, ostep);
n1last = t3;
n2last = t4;
if (flag_checking)
{
t3 = fold_binary (loop->cond_code,
boolean_type_node, t3, t4);
gcc_assert (integer_nonzerop (t3));
}
}
else
{
new_last = t;
n1last = n1cur;
n2last = n2cur;
if (flag_checking)
{
t3 = fold_binary (PLUS_EXPR, itype, n1cur, t3);
t4 = fold_binary (PLUS_EXPR, itype, n2cur, t4);
t3 = fold_binary (loop->cond_code,
boolean_type_node, t3, t4);
gcc_assert (integer_zerop (t3));
}
}
diff = fold_binary (MINUS_EXPR, itype, last, new_last);
}
if (TYPE_UNSIGNED (itype)
&& single_nonrect_cond_code == GT_EXPR)
diff = fold_binary (TRUNC_DIV_EXPR, itype,
fold_unary (NEGATE_EXPR, itype, diff),
fold_unary (NEGATE_EXPR, itype,
ostep));
else
diff = fold_binary (TRUNC_DIV_EXPR, itype, diff, ostep);
diff = fold_convert (long_long_unsigned_type_node, diff);
single_nonrect_count
= fold_binary (MINUS_EXPR, long_long_unsigned_type_node,
single_nonrect_count, diff);
t = NULL_TREE;
}
}
else
t = fold_binary (loop->cond_code, boolean_type_node,
@ -715,10 +836,11 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
*collapse_count = fold_convert_loc (loc, iter_type, count);
if (fd->min_inner_iterations && fd->factor)
{
t = make_tree_vec (3);
t = make_tree_vec (4);
TREE_VEC_ELT (t, 0) = *collapse_count;
TREE_VEC_ELT (t, 1) = fd->min_inner_iterations;
TREE_VEC_ELT (t, 2) = fd->factor;
TREE_VEC_ELT (t, 3) = fd->adjn1;
*collapse_count = t;
}
}
@ -736,6 +858,7 @@ omp_extract_for_data (gomp_for *for_stmt, struct omp_for_data *fd,
gcc_assert (fd->non_rect);
fd->min_inner_iterations = TREE_VEC_ELT (fd->loop.n2, 1);
fd->factor = TREE_VEC_ELT (fd->loop.n2, 2);
fd->adjn1 = TREE_VEC_ELT (fd->loop.n2, 3);
fd->loop.n2 = TREE_VEC_ELT (fd->loop.n2, 0);
}
fd->loop.step = build_int_cst (TREE_TYPE (fd->loop.v), 1);

2
gcc/omp-general.h
View file

@ -85,6 +85,8 @@ struct omp_for_data
outer iterator, depending on which
results in fewer iterations. */
tree factor; /* (m2 - m1) * outer_step / inner_step. */
/* Adjusted n1 of the outer loop in such loop nests (if needed). */
tree adjn1;
};
#define OACC_FN_ATTRIB "oacc function"

230
libgomp/testsuite/libgomp.c/loop-21.c Normal file
View file

@ -0,0 +1,230 @@
/* { dg-do run } */
extern void abort (void);
int x, i, j;
volatile int a, b, c, d, e, f, g, h;
int k[13][27];
int
main ()
{
int niters;
for (i = -4; i < 8; i++)
for (j = 3 * i; j > 2 * i; j--)
k[i + 5][j + 5] = 1;
a = -4; b = 8; c = 1; d = 3; e = 0; f = 2; g = 0; h = -1;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = -4; i < 8; i++)
for (j = 3 * i; j > 2 * i; j--)
{
if (i < -4 || i >= 8 || j > 3 * i || j <= i * 2 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != 8 || j != 14 || x != 7183 || niters != 28)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i < b; i += c)
for (j = d * i + e; j > g + i * f; j += h)
{
if (i < -4 || i >= 8 || j > 3 * i || j <= i * 2 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != 8 || j != 14 || x != 7183 || niters != 28)
abort ();
for (int i = -4; i < 8; i++)
for (int j = 3 * i; j > 2 * i; j--)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
for (i = -2; i < 4; i++)
for (j = -2 * i + 3; j > -3; j -= 2)
k[i + 5][j + 5] = 1;
a = -2; b = 4; c = 1; d = -2; e = 3; f = 0; g = -3; h = -2;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = -2; i < 4; i++)
for (j = -2 * i + 3; j > -3; j -= 2)
{
if (i < -2 || i >= 4 || j <= -3 || j > -2 * i + 3 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/* i != 4 || j != -3 || */x != 3071 || niters != 15)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i < b; i += c)
for (j = d * i + e; j > g + i * f; j += h)
{
if (i < -2 || i >= 4 || j <= -3 || j > -2 * i + 3 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/*i != 4 || j != -3 || */x != 3071 || niters != 15)
abort ();
for (i = -2; i < 4; i++)
for (j = -2 * i + 3; j > -3; j -= 2)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
for (i = 3; i > -3; i--)
for (j = -2 * i + 7; j > 2 * i + 1; j--)
k[i + 5][j + 5] = 1;
a = 3; b = -3; c = -1; d = -2; e = 7; f = 2; g = 1; h = -1;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = 3; i > -3; i--)
for (j = -2 * i + 7; j > 2 * i + 1; j--)
{
if (i <= -3 || i > 3 || j <= 2 * i + 1 || j > -2 * i + 7 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != -3 || j != -3 || x != -1026 || niters != 32)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i > b; i += c)
for (j = d * i + e; j > g + i * f; j += h)
{
if (i <= -3 || i > 3 || j <= 2 * i + 1 || j > -2 * i + 7 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != -3 || j != -3 || x != -1026 || niters != 32)
abort ();
for (i = 3; i > -3; i--)
for (j = -2 * i + 7; j > 2 * i + 1; j--)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
for (i = 3; i > -3; i--)
for (j = 2 * i + 7; j > -2 * i + 1; j--)
k[i + 5][j + 5] = 1;
a = 3; b = -3; c = -1; d = 2; e = 7; f = -2; g = 1; h = -1;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = 3; i > -3; i--)
for (j = 2 * i + 7; j > -2 * i + 1; j--)
{
if (i <= -3 || i > 3 || j <= -2 * i + 1 || j > 2 * i + 7 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/*i != -3 || j != 3 || */x != -1020 || niters != 50)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i > b; i += c)
for (j = d * i + e; j > g + i * f; j += h)
{
if (i <= -3 || i > 3 || j <= -2 * i + 1 || j > 2 * i + 7 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/*i != -3 || j != 3 || */x != -1020 || niters != 50)
abort ();
for (i = 3; i > -3; i--)
for (j = 2 * i + 7; j > -2 * i + 1; j--)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
for (i = 6; i > -6; i--)
for (j = 2 * i + 7; j <= -2 * i + 1; j++)
k[i + 5][j + 5] = 1;
a = 6; b = -6; c = -1; d = 2; e = 7; f = -2; g = 2; h = 1;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = 6; i > -6; i--)
for (j = 2 * i + 7; j <= -2 * i + 1; j++)
{
if (i <= -6 || i > 6 || j < 2 * i + 7 || j >= -2 * i + 2 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != -6 || j != 12 || x != -5109 || niters != 36)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i > b; i += c)
for (j = d * i + e; j < g + i * f; j += h)
{
if (i <= -6 || i > 6 || j < 2 * i + 7 || j >= -2 * i + 2 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (i != -6 || j != 12 || x != -5109 || niters != 36)
abort ();
for (i = 6; i > -6; i--)
for (j = 2 * i + 7; j <= -2 * i + 1; j++)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
for (i = 6; i > -6; i -= 2)
for (j = -2 * i + 7; j <= 2 * i + 1; j++)
k[i + 5][j + 5] = 1;
a = 6; b = -6; c = -2; d = -2; e = 7; f = 2; g = 2; h = 1;
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = 6; i > -6; i -= 2)
for (j = -2 * i + 7; j <= 2 * i + 1; j++)
{
if (i <= -6 || i > 6 || j < -2 * i + 7 || j >= 2 * i + 2 || k[i + 5][j + 5] != 1)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/*i != -6 || j != 15 || */x != 2053 || niters != 33)
abort ();
niters = 0; i = -100; j = -100; x = -100;
#pragma omp parallel for collapse(2) lastprivate (i, j, x) reduction(+:niters)
for (i = a; i > b; i += c)
for (j = d * i + e; j < g + i * f; j += h)
{
if (i <= -6 || i > 6 || j < -2 * i + 7 || j >= 2 * i + 2 || k[i + 5][j + 5] != 2)
abort ();
k[i + 5][j + 5]++;
x = i * 1024 + (j & 1023);
niters++;
}
if (/*i != -6 || j != 15 || */x != 2053 || niters != 33)
abort ();
for (i = 6; i > -6; i -= 2)
for (j = -2 * i + 7; j <= 2 * i + 1; j++)
if (k[i + 5][j + 5] == 3)
k[i + 5][j + 5] = 0;
else
abort ();
return 0;
}