This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[PATCH] Fixup some issues in extract_affine (graphite)
- From: Richard Biener <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 7 Jun 2018 11:45:41 +0200 (CEST)
- Subject: [PATCH] Fixup some issues in extract_affine (graphite)
I've noticed some wrong-code issues as well as missed optimizations
(less 'wrap' stuff).
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
>From 02d00158e8ec62f1c52a8191f6b15c446445a4da Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguenther@suse.de>
Date: Thu, 7 Jun 2018 09:26:22 +0200
Subject: [PATCH] fix-graphite-affine-overflow
* graphite-sese-to-poly.c (extract_affine): Avoid unneded
wrapping. Properly wrap the result of a BIT_NOT_EXPR.
Properly wrap signed arithmetic if overflow wraps.
diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c
index 453f9962e48..4dcc013f6bb 100644
--- a/gcc/graphite-sese-to-poly.c
+++ b/gcc/graphite-sese-to-poly.c
@@ -272,7 +272,8 @@ extract_affine (scop_p s, tree e, __isl_take isl_space *space)
lhs = extract_affine (s, integer_minus_one_node, isl_space_copy (space));
rhs = extract_affine (s, TREE_OPERAND (e, 0), space);
res = isl_pw_aff_sub (lhs, rhs);
- break;
+ /* We need to always wrap the result of a bitwise operation. */
+ return wrap (res, TYPE_PRECISION (type) - (TYPE_UNSIGNED (type) ? 0 : 1));
case NEGATE_EXPR:
lhs = extract_affine (s, TREE_OPERAND (e, 0), isl_space_copy (space));
@@ -285,8 +286,8 @@ extract_affine (scop_p s, tree e, __isl_take isl_space *space)
gcc_assert (! defined_in_sese_p (e, s->scop_info->region));
int dim = parameter_index_in_region (e, s->scop_info);
gcc_assert (dim != -1);
- res = extract_affine_name (dim, space);
- break;
+ /* No need to wrap a parameter. */
+ return extract_affine_name (dim, space);
}
case INTEGER_CST:
@@ -301,11 +302,15 @@ extract_affine (scop_p s, tree e, __isl_take isl_space *space)
/* Signed values, even if overflow is undefined, get modulo-reduced.
But only if not all values of the old type fit in the new. */
if (! TYPE_UNSIGNED (type)
- && ((TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (e, 0)))
+ && ((TYPE_UNSIGNED (itype)
&& TYPE_PRECISION (type) <= TYPE_PRECISION (itype))
|| TYPE_PRECISION (type) < TYPE_PRECISION (itype)))
res = wrap (res, TYPE_PRECISION (type) - 1);
- break;
+ else if (TYPE_UNSIGNED (type)
+ && (!TYPE_UNSIGNED (itype)
+ || TYPE_PRECISION (type) < TYPE_PRECISION (itype)))
+ res = wrap (res, TYPE_PRECISION (type));
+ return res;
}
case NON_LVALUE_EXPR:
@@ -317,7 +322,8 @@ extract_affine (scop_p s, tree e, __isl_take isl_space *space)
break;
}
- if (TYPE_UNSIGNED (type))
+ /* For all wrapping arithmetic wrap the result. */
+ if (TYPE_OVERFLOW_WRAPS (type))
res = wrap (res, TYPE_PRECISION (type));
return res;