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re PR tree-optimization/79408 (Missed VRP optimization of integer modulo) 

PR tree-optimization/79408
	* tree-vrp.c (simplify_div_or_mod_using_ranges): If op1 is not
	constant, but SSA_NAME with a known integer range, use the minimum
	of that range instead of op1 to determine if modulo can be replaced
	with its first operand.

	* gcc.dg/tree-ssa/pr79408.c: New test.

From-SVN: r245273
This commit is contained in:
Jakub Jelinek 2017-02-08 10:21:57 +01:00 committed by Jakub Jelinek
parent 01726bc977
commit 74a15d1424
4 changed files with 71 additions and 10 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2017-02-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/79408
* tree-vrp.c (simplify_div_or_mod_using_ranges): If op1 is not
constant, but SSA_NAME with a known integer range, use the minimum
of that range instead of op1 to determine if modulo can be replaced
with its first operand.
2016-02-08 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
* config/riscv/riscv.c (riscv_build_integer_1): Avoid use of INT16_MAX.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2017-02-08 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/79408
* gcc.dg/tree-ssa/pr79408.c: New test.
2017-02-08 Richard Biener <rguenther@suse.de>
PR tree-optimization/71824

40
gcc/testsuite/gcc.dg/tree-ssa/pr79408.c Normal file
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@ -0,0 +1,40 @@
/* PR tree-optimization/79408 */
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */
void link_error (void);
void
foo (unsigned int x, unsigned int y)
{
if (x > 7312)
return;
if (y <= 7312)
return;
if (x % y != x)
link_error ();
}
void
bar (int x, int y)
{
if (x > 7312 || x < 0)
return;
if (y <= 7312)
return;
if (x % y != x)
link_error ();
}
void
baz (int x, int y)
{
if (x > 7312 || x < -7312)
return;
if (y <= 7312)
return;
if (x % y != x)
link_error ();
}
/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized"} } */

28
gcc/tree-vrp.c
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@ -9226,12 +9226,12 @@ simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt)
return true;
}
/* Simplify a division or modulo operator to a right shift or
bitwise and if the first operand is unsigned or is greater
than zero and the second operand is an exact power of two.
For TRUNC_MOD_EXPR op0 % op1 with constant op1, optimize it
into just op0 if op0's range is known to be a subset of
[-op1 + 1, op1 - 1] for signed and [0, op1 - 1] for unsigned
/* Simplify a division or modulo operator to a right shift or bitwise and
if the first operand is unsigned or is greater than zero and the second
operand is an exact power of two. For TRUNC_MOD_EXPR op0 % op1 with
constant op1 (op1min = op1) or with op1 in [op1min, op1max] range,
optimize it into just op0 if op0's range is known to be a subset of
[-op1min + 1, op1min - 1] for signed and [0, op1min - 1] for unsigned
modulo. */
static bool
@ -9241,17 +9241,25 @@ simplify_div_or_mod_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt)
tree val = NULL;
tree op0 = gimple_assign_rhs1 (stmt);
tree op1 = gimple_assign_rhs2 (stmt);
tree op1min = op1;
value_range *vr = get_value_range (op0);
if (rhs_code == TRUNC_MOD_EXPR
&& TREE_CODE (op1) == INTEGER_CST
&& tree_int_cst_sgn (op1) == 1
&& TREE_CODE (op1) == SSA_NAME)
{
value_range *vr1 = get_value_range (op1);
if (range_int_cst_p (vr1))
op1min = vr1->min;
}
if (rhs_code == TRUNC_MOD_EXPR
&& TREE_CODE (op1min) == INTEGER_CST
&& tree_int_cst_sgn (op1min) == 1
&& range_int_cst_p (vr)
&& tree_int_cst_lt (vr->max, op1))
&& tree_int_cst_lt (vr->max, op1min))
{
if (TYPE_UNSIGNED (TREE_TYPE (op0))
|| tree_int_cst_sgn (vr->min) >= 0
|| tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1),
|| tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1min), op1min),
vr->min))
{
/* If op0 already has the range op0 % op1 has,