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re PR target/30315 (optimize unsigned-add overflow test on x86 to use cpu flags from addl)

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PR target/30315
	* config/i386/i386.h (CANONICALIZE_COMPARISON): Delete.
	* simplify-rtx.c (simplify_relational_operation_1): Add the
	canonicalization from i386.h.
	* doc/md.texi (Canonicalization of Instructions): Document it.

From-SVN: r128305
This commit is contained in:
Rask Ingemann Lambertsen 2007-09-09 21:21:59 +02:00 • committed by Rask Ingemann Lambertsen
parent 0098d80686
commit 921c44189a
4 changed files with 20 additions and 11 deletions
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8
gcc/ChangeLog
View file

@ -1,3 +1,11 @@
2007-09-09 Rask Ingemann Lambertsen <rask@sygehus.dk>
PR target/30315
* config/i386/i386.h (CANONICALIZE_COMPARISON): Delete.
* simplify-rtx.c (simplify_relational_operation_1): Add the
canonicalization from i386.h.
* doc/md.texi (Canonicalization of Instructions): Document it.
2007-09-09 Jan Hubicka <jh@suse.cz>
Dwarakanath Rajagopal <dwarak.rajagopal@amd.com>

10
gcc/config/i386/i386.h
View file

@ -2070,16 +2070,6 @@ do { \
#define SELECT_CC_MODE(OP, X, Y) ix86_cc_mode ((OP), (X), (Y))
/* Canonicalize overflow checks to save on the insn patterns. We change
"a + b < b" into "a + b < a" and "a + b >= b" into "a + b >= a". */
#define CANONICALIZE_COMPARISON(code, op0, op1) \
{ \
if ((code == LTU || code == GEU) \
&& GET_CODE (op0) == PLUS \
&& rtx_equal_p (op1, XEXP (op0, 1))) \
op1 = XEXP (op0, 0); \
}
/* Return nonzero if MODE implies a floating point inequality can be
reversed. */

7
gcc/doc/md.texi
View file

@ -1,5 +1,5 @@
@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1996, 1998, 1999, 2000, 2001,
@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@ -5513,6 +5513,11 @@ An operand of @code{neg}, @code{not}, @code{mult}, @code{plus}, or
@code{minus} is made the first operand under the same conditions as
above.
@item
@code{(ltu (plus @var{a} @var{b}) @var{b})} is converted to
@code{(ltu (plus @var{a} @var{b}) @var{a})}. Likewise with @code{geu} instead
of @code{ltu}.
@item
@code{(minus @var{x} (const_int @var{n}))} is converted to
@code{(plus @var{x} (const_int @var{-n}))}.

6
gcc/simplify-rtx.c
View file

@ -3813,6 +3813,12 @@ simplify_relational_operation_1 (enum rtx_code code, enum machine_mode mode,
}
}
/* Canonicalize (LTU/GEU (PLUS a b) b) as (LTU/GEU (PLUS a b) a). */
if ((code == LTU || code == GEU)
&& GET_CODE (op0) == PLUS
&& rtx_equal_p (op1, XEXP (op0, 1)))
return simplify_gen_relational (code, mode, cmp_mode, op0, XEXP (op0, 0));
if (op1 == const0_rtx)
{
/* Canonicalize (GTU x 0) as (NE x 0). */