The following patch removes (well, the patch only disables)
strict-overflow handling (and thus emitting -Wstrict-overflo diagnostics)
from VRP.
I XFAILed three testcases (well, all three are really the same testcase),
removed on XFAIL and added a testcase for the missed VRP caused by
those INF(OVF) being "sticky".
I'm now re-bootstrapping and testing this on trunk (after I've committed
the -f[no-]strict-overflow removal). The patch bootstrapped and
tested ok a week ago.
I'm not sure if I will commit the patch as-is or if I actually remove
(some) of the strict-overflow machinery itself in the initial patch.
Comments still appreciated. And yes, it should be easily possible
to preserve the warning on the testcase -- even from within
the FE itself I guess but also from VRP (the IV is not SCEV
analyzable otherwise -Waggressive-loop-optimizations would warn).
Richard.
2017-05-02 Richard Biener <rguent...@suse.de>
PR tree-optimization/31130
* tree-vrp.c (needs_overflow_infinity): Return always false.
(set_value_range_to_nonnegative): Properly guard
supports_overflow_infinity.
* gcc.dg/Wstrict-overflow-12.c: XFAIL.
* gcc.dg/Wstrict-overflow-13.c: Likewise.
* gcc.dg/Wstrict-overflow-21.c: Likewise.
* gcc.dg/pr52904.c: Remove XFAIL.
* gcc.dg/tree-ssa/vrp113.c: New testcase.
Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c.orig 2017-04-28 11:24:38.953886334 +0200
--- gcc/tree-vrp.c 2017-05-02 15:14:48.438675683 +0200
*************** vrp_val_is_min (const_tree val)
*** 220,228 ****
TYPE_{MIN,MAX}_VALUE. */
static inline bool
! needs_overflow_infinity (const_tree type)
{
! return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
}
/* Return whether TYPE can support our overflow infinity
--- 220,228 ----
TYPE_{MIN,MAX}_VALUE. */
static inline bool
! needs_overflow_infinity (const_tree)
{
! return false;
}
/* Return whether TYPE can support our overflow infinity
*************** set_value_range_to_nonnegative (value_ra
*** 558,564 ****
{
tree zero;
! if (overflow_infinity && !supports_overflow_infinity (type))
{
set_value_range_to_varying (vr);
return;
--- 558,566 ----
{
tree zero;
! if (overflow_infinity
! && (needs_overflow_infinity (type)
! && !supports_overflow_infinity (type)))
{
set_value_range_to_varying (vr);
return;
*************** set_value_range_to_nonnegative (value_ra
*** 566,572 ****
zero = build_int_cst (type, 0);
set_value_range (vr, VR_RANGE, zero,
! (overflow_infinity
? positive_overflow_infinity (type)
: TYPE_MAX_VALUE (type)),
vr->equiv);
--- 568,574 ----
zero = build_int_cst (type, 0);
set_value_range (vr, VR_RANGE, zero,
! (overflow_infinity && needs_overflow_infinity (type)
? positive_overflow_infinity (type)
: TYPE_MAX_VALUE (type)),
vr->equiv);
Index: gcc/testsuite/gcc.dg/Wstrict-overflow-12.c
===================================================================
*** gcc/testsuite/gcc.dg/Wstrict-overflow-12.c.orig 2007-11-30
13:59:34.000000000 +0100
--- gcc/testsuite/gcc.dg/Wstrict-overflow-12.c 2017-05-02 15:19:32.259012861
+0200
*************** int
*** 10,16 ****
foo ()
{
int i, bits;
! for (i = 1, bits = 1; i > 0; i += i) /* { dg-warning "assuming signed
overflow does not occur" "correct warning" } */
++bits;
return bits;
}
--- 10,16 ----
foo ()
{
int i, bits;
! for (i = 1, bits = 1; i > 0; i += i) /* { dg-warning "assuming signed
overflow does not occur" "correct warning" { xfail *-*-* } } */
++bits;
return bits;
}
Index: gcc/testsuite/gcc.dg/Wstrict-overflow-13.c
===================================================================
*** gcc/testsuite/gcc.dg/Wstrict-overflow-13.c.orig 2007-11-30
13:59:35.000000000 +0100
--- gcc/testsuite/gcc.dg/Wstrict-overflow-13.c 2017-05-02 15:20:03.927497363
+0200
*************** int
*** 11,17 ****
foo ()
{
int j;
! for (j = 1; 0 < j; j *= 2) /* { dg-warning "assuming signed overflow does
not occur" "correct warning" } */
if (! bigtime_test (j))
return 1;
return 0;
--- 11,17 ----
foo ()
{
int j;
! for (j = 1; 0 < j; j *= 2) /* { dg-warning "assuming signed overflow does
not occur" "correct warning" { xfail *-*-* } } */
if (! bigtime_test (j))
return 1;
return 0;
Index: gcc/testsuite/gcc.dg/Wstrict-overflow-21.c
===================================================================
*** gcc/testsuite/gcc.dg/Wstrict-overflow-21.c.orig 2008-01-22
15:53:57.000000000 +0100
--- gcc/testsuite/gcc.dg/Wstrict-overflow-21.c 2017-05-02 15:20:18.087714039
+0200
*************** int
*** 5,11 ****
foo ()
{
int i, bits;
! for (i = 1, bits = 1; i > 0; i += i) /* { dg-warning "assuming signed
overflow does not occur" "correct warning" } */
++bits;
return bits;
}
--- 5,11 ----
foo ()
{
int i, bits;
! for (i = 1, bits = 1; i > 0; i += i) /* { dg-warning "assuming signed
overflow does not occur" "correct warning" { xfail *-*-* } } */
++bits;
return bits;
}
Index: gcc/testsuite/gcc.dg/pr52904.c
===================================================================
*** gcc/testsuite/gcc.dg/pr52904.c.orig 2016-08-17 13:59:02.625248245 +0200
--- gcc/testsuite/gcc.dg/pr52904.c 2017-05-02 15:21:42.157000890 +0200
*************** wait_reading_process_output (void)
*** 14,20 ****
nfds++;
}
! if (nfds < 0) /* { dg-bogus "assuming signed overflow does not occur" "" {
xfail *-*-* } } */
return 1;
return 0;
}
--- 14,20 ----
nfds++;
}
! if (nfds < 0) /* { dg-bogus "assuming signed overflow does not occur" "" }
*/
return 1;
return 0;
}
Index: gcc/testsuite/gcc.dg/tree-ssa/vrp113.c
===================================================================
*** /dev/null 1970-01-01 00:00:00.000000000 +0000
--- gcc/testsuite/gcc.dg/tree-ssa/vrp113.c 2017-05-02 15:32:03.314531397
+0200
***************
*** 0 ****
--- 1,24 ----
+ /* { dg-do link } */
+ /* { dg-options "-O2 -fdump-tree-fre1 -fdump-tree-evrp" } */
+
+ extern void link_error ();
+ void foo (int a)
+ {
+ if (a < 0)
+ {
+ int y;
+ a = -a;
+ y = a / 7;
+ y = y * 2;
+ if (y > 1 << 30)
+ link_error ();
+ }
+ }
+
+ int main()
+ {
+ return 0;
+ }
+
+ /* { dg-final { scan-tree-dump-times "link_error" 1 "fre1" } } */
+ /* { dg-final { scan-tree-dump-times "link_error" 0 "evrp" } } */
