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tree-optimization/94234 - Fold plusminus_mult expr with multi-use operands

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2020-09-03  Feng Xue  <fxue@os.amperecomputing.com>

gcc/
	PR tree-optimization/94234
	* genmatch.c (dt_simplify::gen_1): Emit check on final simplification
	result when "!" is specified on toplevel output expr.
	* match.pd ((A * C) +- (B * C) -> (A +- B) * C): Allow folding on expr
	with multi-use operands if final result is a simple gimple value.

gcc/testsuite/
	PR tree-optimization/94234
	* gcc.dg/pr94234-2.c: New test.
This commit is contained in:
Feng Xue 2020-09-01 17:17:58 +08:00
parent 50a71cd018
commit f9d2def016
3 changed files with 60 additions and 11 deletions
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10
gcc/genmatch.c
View file

@ -3426,8 +3426,14 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple, operand *result)
/* Re-fold the toplevel result. It's basically an embedded
gimple_build w/o actually building the stmt. */
if (!is_predicate)
fprintf_indent (f, indent,
"res_op->resimplify (lseq, valueize);\n");
{
fprintf_indent (f, indent,
"res_op->resimplify (lseq, valueize);\n");
if (e->force_leaf)
fprintf_indent (f, indent,
"if (!maybe_push_res_to_seq (res_op, NULL)) "
"goto %s;\n", fail_label);
}
}
else if (result->type == operand::OP_CAPTURE
|| result->type == operand::OP_C_EXPR)

22
gcc/match.pd
View file

@ -2570,15 +2570,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(for plusminus (plus minus)
(simplify
(plusminus (mult:cs@3 @0 @1) (mult:cs@4 @0 @2))
(if ((!ANY_INTEGRAL_TYPE_P (type)
|| TYPE_OVERFLOW_WRAPS (type)
|| (INTEGRAL_TYPE_P (type)
&& tree_expr_nonzero_p (@0)
&& expr_not_equal_to (@0, wi::minus_one (TYPE_PRECISION (type)))))
/* If @1 +- @2 is constant require a hard single-use on either
original operand (but not on both). */
&& (single_use (@3) || single_use (@4)))
(mult (plusminus @1 @2) @0)))
(if (!ANY_INTEGRAL_TYPE_P (type)
|| TYPE_OVERFLOW_WRAPS (type)
|| (INTEGRAL_TYPE_P (type)
&& tree_expr_nonzero_p (@0)
&& expr_not_equal_to (@0, wi::minus_one (TYPE_PRECISION (type)))))
(if (single_use (@3) || single_use (@4))
/* If @1 +- @2 is constant require a hard single-use on either
original operand (but not on both). */
(mult (plusminus @1 @2) @0)
#if GIMPLE
(mult! (plusminus @1 @2) @0)
#endif
)))
/* We cannot generate constant 1 for fract. */
(if (!ALL_FRACT_MODE_P (TYPE_MODE (type)))
(simplify

39
gcc/testsuite/gcc.dg/pr94234-2.c Normal file
View file

@ -0,0 +1,39 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-forwprop1" } */
int use_fn (int a);
int foo (int n)
{
int b1 = 8 * (n + 1);
int b2 = 8 * n;
use_fn (b1 ^ b2);
return b1 - b2;
}
unsigned goo (unsigned m_param, unsigned n_param)
{
unsigned b1 = m_param * (n_param + 2);
unsigned b2 = m_param * (n_param + 1);
use_fn (b1 ^ b2);
return b1 - b2;
}
unsigned hoo (unsigned k_param)
{
unsigned b1 = k_param * 28;
unsigned b2 = k_param * 15;
unsigned b3 = k_param * 12;
use_fn (b1 ^ b2 ^ b3);
return (b1 - b2) - b3;
}
/* { dg-final { scan-tree-dump-times "return 8;" 1 "forwprop1" } } */
/* { dg-final { scan-tree-dump-times "return m_param" 1 "forwprop1" } } */
/* { dg-final { scan-tree-dump-not "return k_param" "forwprop1" } } */