This re-surrects Josephs patch to fix PR35634 - the fact that
the C frontend family does not properly promote the expression
operands of self-modify expressions. Accounting for this during
gimplification is indeed easiest (as long as fold isn't too clever
with the expressions in unpromoted form). The patch, instead of
promoting to int/unsigned int uses an unsigned type for the
computation where otherwise undefined behavior would arise from
the computation in a type with lower precision. That avoids
most of the vectorizer regressions with the earlier patch.
The remaining three regressions are fixed with the
vect_can_advance_ivs_p hunk.
Bootstrapped and tested on x86_64-unknown-linux-gnu without
the vect_can_advance_ivs_p hunk, re-testing with that.
Ok for trunk? (I don't think this kind of patch qualifies for
backporting)
Thanks,
Richard.
2008-04-17 Richard Guenther <rguent...@suse.de>
PR c/35634
* gimple.h (gimplify_self_mod_expr): Declare.
* gimplify.c (gimplify_self_mod_expr): Export. Take a different
type for performing the arithmetic in.
(gimplify_expr): Adjust.
* tree-vect-loop-manip.c (vect_can_advance_ivs_p): Strip
sign conversions we can re-apply after adjusting the IV.
c-family/
* c-gimplify.c (c_gimplify_expr): Gimplify self-modify expressions
here and use a type with proper overflow behavior for types that would
need to be promoted for the arithmetic.
* gcc.dg/torture/pr35634.c: New testcase.
* g++.dg/torture/pr35634.C: Likewise.
* gcc.dg/vect/pr18536.c: Mark worker function noinline.
Index: gcc/testsuite/g++.dg/torture/pr35634.C
===================================================================
*** /dev/null 1970-01-01 00:00:00.000000000 +0000
--- gcc/testsuite/g++.dg/torture/pr35634.C 2012-11-27 15:49:46.387585847
+0100
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-do run } */
+
+ extern "C" void abort (void);
+ extern "C" void exit (int);
+
+ void foo (int i)
+ {
+ static int n;
+ if (i < -128 || i > 127)
+ abort ();
+ if (++n > 1000)
+ exit (0);
+ }
+
+ int main ()
+ {
+ char c;
+ for (c = 0; ; c++) foo (c);
+ }
Index: gcc/testsuite/gcc.dg/torture/pr35634.c
===================================================================
*** /dev/null 1970-01-01 00:00:00.000000000 +0000
--- gcc/testsuite/gcc.dg/torture/pr35634.c 2012-11-27 15:49:46.424585859
+0100
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-do run } */
+
+ void abort (void);
+ void exit (int);
+
+ void foo (int i)
+ {
+ static int n;
+ if (i < -128 || i > 127)
+ abort ();
+ if (++n > 1000)
+ exit (0);
+ }
+
+ int main ()
+ {
+ char c;
+ for (c = 0; ; c++) foo (c);
+ }
Index: gcc/gimple.h
===================================================================
*** gcc/gimple.h.orig 2012-11-27 14:27:24.000000000 +0100
--- gcc/gimple.h 2012-11-27 15:49:46.424585859 +0100
*************** extern enum gimplify_status gimplify_exp
*** 979,984 ****
--- 979,986 ----
bool (*) (tree), fallback_t);
extern void gimplify_type_sizes (tree, gimple_seq *);
extern void gimplify_one_sizepos (tree *, gimple_seq *);
+ enum gimplify_status gimplify_self_mod_expr (tree *, gimple_seq *, gimple_seq
*,
+ bool, tree);
extern bool gimplify_stmt (tree *, gimple_seq *);
extern gimple gimplify_body (tree, bool);
extern void push_gimplify_context (struct gimplify_ctx *);
Index: gcc/gimplify.c
===================================================================
*** gcc/gimplify.c.orig 2012-11-27 14:27:24.000000000 +0100
--- gcc/gimplify.c 2012-11-27 15:49:46.425585857 +0100
*************** gimplify_compound_lval (tree *expr_p, gi
*** 2319,2327 ****
WANT_VALUE is nonzero iff we want to use the value of this expression
in another expression. */
! static enum gimplify_status
gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
! bool want_value)
{
enum tree_code code;
tree lhs, lvalue, rhs, t1;
--- 2319,2327 ----
WANT_VALUE is nonzero iff we want to use the value of this expression
in another expression. */
! enum gimplify_status
gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
! bool want_value, tree arith_type)
{
enum tree_code code;
tree lhs, lvalue, rhs, t1;
*************** gimplify_self_mod_expr (tree *expr_p, gi
*** 2382,2408 ****
return ret;
}
/* For POINTERs increment, use POINTER_PLUS_EXPR. */
if (POINTER_TYPE_P (TREE_TYPE (lhs)))
{
rhs = convert_to_ptrofftype_loc (loc, rhs);
if (arith_code == MINUS_EXPR)
rhs = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (rhs), rhs);
! arith_code = POINTER_PLUS_EXPR;
}
if (postfix)
{
- tree t2 = get_initialized_tmp_var (lhs, pre_p, NULL);
- t1 = build2 (arith_code, TREE_TYPE (*expr_p), t2, rhs);
gimplify_assign (lvalue, t1, pre_p);
gimplify_seq_add_seq (orig_post_p, post);
! *expr_p = t2;
return GS_ALL_DONE;
}
else
{
- t1 = build2 (arith_code, TREE_TYPE (*expr_p), lhs, rhs);
*expr_p = build2 (MODIFY_EXPR, TREE_TYPE (lvalue), lvalue, t1);
return GS_OK;
}
--- 2382,2413 ----
return ret;
}
+ if (postfix)
+ lhs = get_initialized_tmp_var (lhs, pre_p, NULL);
+
/* For POINTERs increment, use POINTER_PLUS_EXPR. */
if (POINTER_TYPE_P (TREE_TYPE (lhs)))
{
rhs = convert_to_ptrofftype_loc (loc, rhs);
if (arith_code == MINUS_EXPR)
rhs = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (rhs), rhs);
! t1 = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (*expr_p), lhs, rhs);
}
+ else
+ t1 = fold_convert (TREE_TYPE (*expr_p),
+ fold_build2 (arith_code, arith_type,
+ fold_convert (arith_type, lhs),
+ fold_convert (arith_type, rhs)));
if (postfix)
{
gimplify_assign (lvalue, t1, pre_p);
gimplify_seq_add_seq (orig_post_p, post);
! *expr_p = lhs;
return GS_ALL_DONE;
}
else
{
*expr_p = build2 (MODIFY_EXPR, TREE_TYPE (lvalue), lvalue, t1);
return GS_OK;
}
*************** gimplify_expr (tree *expr_p, gimple_seq
*** 7111,7117 ****
case PREINCREMENT_EXPR:
case PREDECREMENT_EXPR:
ret = gimplify_self_mod_expr (expr_p, pre_p, post_p,
! fallback != fb_none);
break;
case ARRAY_REF:
--- 7116,7123 ----
case PREINCREMENT_EXPR:
case PREDECREMENT_EXPR:
ret = gimplify_self_mod_expr (expr_p, pre_p, post_p,
! fallback != fb_none,
! TREE_TYPE (*expr_p));
break;
case ARRAY_REF:
Index: gcc/c-family/c-gimplify.c
===================================================================
*** gcc/c-family/c-gimplify.c.orig 2012-11-27 14:27:24.000000000 +0100
--- gcc/c-family/c-gimplify.c 2012-11-27 15:50:08.796585070 +0100
*************** c_gimplify_expr (tree *expr_p, gimple_se
*** 172,187 ****
{
enum tree_code code = TREE_CODE (*expr_p);
! /* This is handled mostly by gimplify.c, but we have to deal with
! not warning about int x = x; as it is a GCC extension to turn off
! this warning but only if warn_init_self is zero. */
! if (code == DECL_EXPR
! && TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL
! && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
! && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
! && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) == DECL_EXPR_DECL (*expr_p))
! && !warn_init_self)
! TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1;
return GS_UNHANDLED;
}
--- 172,208 ----
{
enum tree_code code = TREE_CODE (*expr_p);
! switch (code)
! {
! case DECL_EXPR:
! /* This is handled mostly by gimplify.c, but we have to deal with
! not warning about int x = x; as it is a GCC extension to turn off
! this warning but only if warn_init_self is zero. */
! if (TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL
! && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
! && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
! && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p)) == DECL_EXPR_DECL
(*expr_p))
! && !warn_init_self)
! TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1;
! break;
!
! case PREINCREMENT_EXPR:
! case PREDECREMENT_EXPR:
! case POSTINCREMENT_EXPR:
! case POSTDECREMENT_EXPR:
! {
! tree type = TREE_TYPE (TREE_OPERAND (*expr_p, 0));
! if (INTEGRAL_TYPE_P (type) && c_promoting_integer_type_p (type))
! {
! if (TYPE_OVERFLOW_UNDEFINED (type))
! type = unsigned_type_for (type);
! return gimplify_self_mod_expr (expr_p, pre_p, post_p, 1, type);
! }
! break;
! }
!
! default:;
! }
return GS_UNHANDLED;
}
Index: gcc/testsuite/gcc.dg/vect/pr18536.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/pr18536.c.orig 2006-02-07 11:14:12.000000000
+0100
--- gcc/testsuite/gcc.dg/vect/pr18536.c 2012-11-27 15:59:50.510564950 +0100
***************
*** 5,11 ****
#define N 16
! int main1 (short a, short *b)
{
while (++a < 4) *b++ = 2;
--- 5,11 ----
#define N 16
! __attribute__ ((noinline)) int main1 (short a, short *b)
{
while (++a < 4) *b++ = 2;
Index: gcc/tree-vect-loop-manip.c
===================================================================
*** gcc/tree-vect-loop-manip.c.orig 2012-11-26 12:40:21.000000000 +0100
--- gcc/tree-vect-loop-manip.c 2012-11-27 16:10:37.601542471 +0100
*************** vect_can_advance_ivs_p (loop_vec_info lo
*** 1727,1732 ****
--- 1727,1733 ----
return false;
}
+ STRIP_NOPS (access_fn);
if (dump_enabled_p ())
{
dump_printf_loc (MSG_NOTE, vect_location,
