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#! /bin/sh -e
# DP: Fix (neg (lt X 0)) optimization (PR rtl-optimization/33148)
dir=
if [ $# -eq 3 -a "$2" = '-d' ]; then
pdir="-d $3"
dir="$3/"
elif [ $# -ne 1 ]; then
echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
exit 1
fi
case "$1" in
-patch)
patch $pdir -f --no-backup-if-mismatch -p0 < $0
;;
-unpatch)
patch $pdir -f --no-backup-if-mismatch -R -p0 < $0
;;
*)
echo >&2 "`basename $0`: script expects -patch|-unpatch as argument"
exit 1
esac
exit 0
From: Jakub Jelinek <jakub@redhat.com>
Sender: gcc-patches-owner@gcc.gnu.org
To: gcc-patches@gcc.gnu.org
Subject: [PATCH] Fix (neg (lt X 0)) optimization (PR rtl-optimization/33148)
Date: Mon, 27 Aug 2007 07:22:44 -0400
Hi!
PR25600 change introduced an optimization of (neg (lt x 0)) to
(ashirtrt x C), but it is not checking whether x's mode is suitable
for it. As it checks that op1 is const0_rtx, I believe MODE_FLOAT
or VECTOR_MODE_P modes are not a problem, CC modes can certainly appear
in LT's first operand with second operand const0_rtx.
So, when we optimize
(neg:DI (lt:DI (reg:CC ...) (const_int 0)))
we create something like
(sign_extend:DI (ashirtrt:CC (reg:CC ...) (const_int 31)))
which is IMHO invalid RTL, ashirtrt is documented on fixed point modes
only (guess vector modes aren't listed just by omission) and so is
sign_extend.
Ok for 4.2/trunk?
2007-08-27 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/33148
* simplify-rtx.c (simplify_unary_operation_1): Only optimize
(neg (lt X 0)) if X has scalar int mode.
* gcc.c-torture/compile/20070827-1.c: New test.
--- gcc/simplify-rtx.c.jj 2007-08-27 10:15:33.000000000 +0200
+++ gcc/simplify-rtx.c 2007-08-27 12:12:51.000000000 +0200
@@ -583,7 +583,8 @@ simplify_unary_operation_1 (enum rtx_cod
/* (neg (lt x 0)) is (ashiftrt X C) if STORE_FLAG_VALUE is 1. */
/* (neg (lt x 0)) is (lshiftrt X C) if STORE_FLAG_VALUE is -1. */
if (GET_CODE (op) == LT
- && XEXP (op, 1) == const0_rtx)
+ && XEXP (op, 1) == const0_rtx
+ && SCALAR_INT_MODE_P (GET_MODE (XEXP (op, 0))))
{
enum machine_mode inner = GET_MODE (XEXP (op, 0));
int isize = GET_MODE_BITSIZE (inner);
--- gcc/testsuite/gcc.c-torture/compile/20070827-1.c.jj 2007-08-27 12:17:20.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/compile/20070827-1.c 2007-08-27 12:15:45.000000000 +0200
@@ -0,0 +1,20 @@
+/* PR rtl-optimization/33148 */
+
+int
+foo (unsigned int *p, int *q, unsigned int w, unsigned int b)
+{
+ unsigned int i;
+ int mask;
+
+ if (q[0] < q[1])
+ mask = 0xff;
+ else
+ mask = 0;
+
+ for (i = 0; 8 * i < w; i++)
+ {
+ b ^= mask;
+ *p++ = b;
+ }
+ return 0;
+}
Jakub
|
