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[simplify-rtx] (GTU (PLUS a C) (C - 1)) --> (LTU a -C) 

* simplify-rtx.c (simplify_relational_operation_1): Add transformation
	(GTU (PLUS a C) (C - 1)) --> (LTU a -C).

	* gcc.target/aarch64/gtu_to_ltu_cmp_1.c: New test.
	* gcc.target/aarch64/gtu_to_ltu_cmp_2.c: New test.

From-SVN: r240238
This commit is contained in:
Kyrylo Tkachov 2016-09-19 16:15:57 +00:00 committed by Kyrylo Tkachov
parent ee1ab3e3c2
commit 5fa9e6441f
5 changed files with 47 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2016-09-19 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
* simplify-rtx.c (simplify_relational_operation_1): Add transformation
(GTU (PLUS a C) (C - 1)) --> (LTU a -C).
2016-09-19 Segher Boessenkool <segher@kernel.crashing.org>
* target.def (lra_p): Wordsmithing.

13
gcc/simplify-rtx.c
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@ -4650,6 +4650,19 @@ simplify_relational_operation_1 (enum rtx_code code, machine_mode mode,
cmp_mode, XEXP (op0, 0), new_cmp);
}
/* (GTU (PLUS a C) (C - 1)) where C is a non-zero constant can be
transformed into (LTU a -C). */
if (code == GTU && GET_CODE (op0) == PLUS && CONST_INT_P (op1)
&& CONST_INT_P (XEXP (op0, 1))
&& (UINTVAL (op1) == UINTVAL (XEXP (op0, 1)) - 1)
&& XEXP (op0, 1) != const0_rtx)
{
rtx new_cmp
= simplify_gen_unary (NEG, cmp_mode, XEXP (op0, 1), cmp_mode);
return simplify_gen_relational (LTU, mode, cmp_mode,
XEXP (op0, 0), new_cmp);
}
/* Canonicalize (LTU/GEU (PLUS a b) b) as (LTU/GEU (PLUS a b) a). */
if ((code == LTU || code == GEU)
&& GET_CODE (op0) == PLUS

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-09-19 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
* gcc.target/aarch64/gtu_to_ltu_cmp_1.c: New test.
* gcc.target/aarch64/gtu_to_ltu_cmp_2.c: New test.
2016-09-19 Jakub Jelinek <jakub@redhat.com>
Jan Hubicka <jh@suse.cz>

13
gcc/testsuite/gcc.target/aarch64/gtu_to_ltu_cmp_1.c Normal file
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@ -0,0 +1,13 @@
/* { dg-do compile } */
/* { dg-options "-O2" } */
int
f1 (int x, int t)
{
if (x == -1 || x == -2)
t = 1;
return t;
}
/* { dg-final { scan-assembler-times "cmn\\tw\[0-9\]+, #2" 1 } } */

11
gcc/testsuite/gcc.target/aarch64/gtu_to_ltu_cmp_2.c Normal file
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@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-O2" } */
unsigned int
foo (unsigned int a, unsigned int b)
{
return (a + 10) > 9;
}
/* { dg-final { scan-assembler-times "cmn\\tw\[0-9\]+" 1 } } */
/* { dg-final { scan-assembler-not "add\\tw\[0-9\]+" } } */