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re PR tree-optimization/68529 (scev failed for while(i--))

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PR tree-optimization/68529
	* tree-ssa-loop-niter.c (number_of_iterations_ne): Add new param.
	Compute no-overflow information for control iv.
	(number_of_iterations_lt, number_of_iterations_le): Add new param.
	(number_of_iterations_cond): Pass new argument to above functions.

	PR tree-optimization/68529
	* gcc.dg/tree-ssa/pr68529-1.c: New test.
	* gcc.dg/tree-ssa/pr68529-2.c: New test.
	* gcc.dg/tree-ssa/pr68529-3.c: New test.

From-SVN: r231097
This commit is contained in:
Bin Cheng 2015-12-01 05:22:16 +00:00 • committed by Bin Cheng
parent 6ea98dee20
commit cdf66caf4f
6 changed files with 139 additions and 15 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2015-12-01 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/68529
* tree-ssa-loop-niter.c (number_of_iterations_ne): Add new param.
Compute no-overflow information for control iv.
(number_of_iterations_lt, number_of_iterations_le): Add new param.
(number_of_iterations_cond): Pass new argument to above functions.
2015-11-30 Jan Hubicka <hubicka@ucw.cz>
* ipa-inline-transform.c (inline_call): Drop -fstrict-aliasing when

7
gcc/testsuite/ChangeLog
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@ -1,3 +1,10 @@
2015-12-01 Bin Cheng <bin.cheng@arm.com>
PR tree-optimization/68529
* gcc.dg/tree-ssa/pr68529-1.c: New test.
* gcc.dg/tree-ssa/pr68529-2.c: New test.
* gcc.dg/tree-ssa/pr68529-3.c: New test.
2015-11-30 Jan Hubicka <hubicka@ucw.cz>
* gcc.dg/lto/alias-1_0.c: New testcase.

20
gcc/testsuite/gcc.dg/tree-ssa/pr68529-1.c Normal file
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@ -0,0 +1,20 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-loop-distribution -ftree-loop-distribute-patterns -fdump-tree-ldist-details" } */
void bar(char *s);
int foo()
{
char c[10000] = {};
unsigned short nchar = 9999;
while(nchar-- != 0)
{
c[nchar] = 'A';
}
bar (c);
return 0;
}
/* { dg-final { scan-tree-dump "distributed: split to 0 loops and 1 library calls" "ldist" } } */
/* { dg-final { scan-tree-dump "generated memset" "ldist" } } */

23
gcc/testsuite/gcc.dg/tree-ssa/pr68529-2.c Normal file
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@ -0,0 +1,23 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-loop-distribution -ftree-loop-distribute-patterns -fdump-tree-ldist-details" } */
void bar(char *s);
int foo(unsigned short l)
{
char c[10000] = {};
unsigned short nchar = 9999;
if (nchar <= l)
return -1;
while(nchar-- != l)
{
c[nchar] = 'A';
}
bar (c);
return 0;
}
/* { dg-final { scan-tree-dump "distributed: split to 0 loops and 1 library calls" "ldist" } } */
/* { dg-final { scan-tree-dump "generated memset" "ldist" } } */

47
gcc/testsuite/gcc.dg/tree-ssa/pr68529-3.c Normal file
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@ -0,0 +1,47 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-loop-distribution -ftree-loop-distribute-patterns -fdump-tree-ldist-details" } */
void bar(char *s);
int foo1(unsigned short l)
{
char c[10000] = {};
unsigned short nchar = 9999;
while(nchar-- != l)
{
c[nchar] = 'A';
}
bar (c);
return 0;
}
int foo2()
{
char c[100000] = {};
unsigned short nchar;
for (nchar = 0; nchar != 1000; --nchar)
{
c[nchar] = 'A';
}
bar (c);
return 0;
}
int foo3()
{
char c[100000] = {};
unsigned short nchar;
for (nchar = 0; nchar != 1000; nchar += 3)
{
c[nchar] = 'A';
}
bar (c);
return 0;
}
/* { dg-final { scan-tree-dump-times "failed: evolution of offset is not affine" 3 "ldist" } } */

49
gcc/tree-ssa-loop-niter.c
View file

@ -957,13 +957,14 @@ number_of_iterations_ne_max (mpz_t bnd, bool no_overflow, tree c, tree s,
bounds on the difference FINAL - IV->base. */
static bool
number_of_iterations_ne (tree type, affine_iv *iv, tree final,
struct tree_niter_desc *niter, bool exit_must_be_taken,
bounds *bnds)
number_of_iterations_ne (struct loop *loop, tree type, affine_iv *iv,
tree final, struct tree_niter_desc *niter,
bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
tree s, c, d, bits, assumption, tmp, bound;
mpz_t max;
tree e;
niter->control = *iv;
niter->bound = final;
@ -998,6 +999,23 @@ number_of_iterations_ne (tree type, affine_iv *iv, tree final,
TYPE_SIGN (niter_type));
mpz_clear (max);
/* Compute no-overflow information for the control iv. Note we are
handling NE_EXPR, if iv base equals to final value, the loop exits
immediately, and the iv does not overflow. */
if (tree_int_cst_sign_bit (iv->step))
e = fold_build2 (GE_EXPR, boolean_type_node, iv->base, final);
else
e = fold_build2 (LE_EXPR, boolean_type_node, iv->base, final);
e = simplify_using_initial_conditions (loop, e);
if (integer_onep (e)
&& (integer_onep (s)
|| (TREE_CODE (c) == INTEGER_CST
&& TREE_CODE (s) == INTEGER_CST
&& wi::mod_trunc (c, s, TYPE_SIGN (type)) == 0)))
{
niter->control.no_overflow = true;
}
/* First the trivial cases -- when the step is 1. */
if (integer_onep (s))
{
@ -1361,8 +1379,8 @@ assert_loop_rolls_lt (tree type, affine_iv *iv0, affine_iv *iv1,
that the exit must be taken eventually. */
static bool
number_of_iterations_lt (tree type, affine_iv *iv0, affine_iv *iv1,
struct tree_niter_desc *niter,
number_of_iterations_lt (struct loop *loop, tree type, affine_iv *iv0,
affine_iv *iv1, struct tree_niter_desc *niter,
bool exit_must_be_taken, bounds *bnds)
{
tree niter_type = unsigned_type_for (type);
@ -1434,7 +1452,8 @@ number_of_iterations_lt (tree type, affine_iv *iv0, affine_iv *iv1,
zps does not overflow. */
zps.no_overflow = true;
return number_of_iterations_ne (type, &zps, delta, niter, true, bnds);
return number_of_iterations_ne (loop, type, &zps,
delta, niter, true, bnds);
}
/* Make sure that the control iv does not overflow. */
@ -1473,9 +1492,9 @@ number_of_iterations_lt (tree type, affine_iv *iv0, affine_iv *iv1,
is the case). BNDS bounds the difference IV1->base - IV0->base. */
static bool
number_of_iterations_le (tree type, affine_iv *iv0, affine_iv *iv1,
struct tree_niter_desc *niter, bool exit_must_be_taken,
bounds *bnds)
number_of_iterations_le (struct loop *loop, tree type, affine_iv *iv0,
affine_iv *iv1, struct tree_niter_desc *niter,
bool exit_must_be_taken, bounds *bnds)
{
tree assumption;
tree type1 = type;
@ -1523,7 +1542,7 @@ number_of_iterations_le (tree type, affine_iv *iv0, affine_iv *iv1,
bounds_add (bnds, 1, type1);
return number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
return number_of_iterations_lt (loop, type, iv0, iv1, niter, exit_must_be_taken,
bnds);
}
@ -1698,18 +1717,18 @@ number_of_iterations_cond (struct loop *loop,
{
case NE_EXPR:
gcc_assert (integer_zerop (iv1->step));
ret = number_of_iterations_ne (type, iv0, iv1->base, niter,
ret = number_of_iterations_ne (loop, type, iv0, iv1->base, niter,
exit_must_be_taken, &bnds);
break;
case LT_EXPR:
ret = number_of_iterations_lt (type, iv0, iv1, niter, exit_must_be_taken,
&bnds);
ret = number_of_iterations_lt (loop, type, iv0, iv1, niter,
exit_must_be_taken, &bnds);
break;
case LE_EXPR:
ret = number_of_iterations_le (type, iv0, iv1, niter, exit_must_be_taken,
&bnds);
ret = number_of_iterations_le (loop, type, iv0, iv1, niter,
exit_must_be_taken, &bnds);
break;
default: