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re PR c/61240 (Incorrect warning "integer overflow in expression" on pointer-pointer subtraction)

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PR c/61240
	* match.pd ((P + A) - P, P - (P + A), (P + A) - (P + B)): For
	pointer_diff optimizations use view_convert instead of convert.

	* gcc.dg/pr61240.c: New test.

From-SVN: r256838
This commit is contained in:
Jakub Jelinek 2018-01-18 09:29:14 +01:00 • committed by Jakub Jelinek
parent fcf7923742
commit 8ae438811f
4 changed files with 44 additions and 3 deletions
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6
gcc/ChangeLog
View file

@ -1,3 +1,9 @@
2018-01-18 Jakub Jelinek <jakub@redhat.com>
PR c/61240
* match.pd ((P + A) - P, P - (P + A), (P + A) - (P + B)): For
pointer_diff optimizations use view_convert instead of convert.
2018-01-17 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
* config/rs6000/rs6000.md (*call_indirect_nonlocal_sysv<mode>):

16
gcc/match.pd
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@ -1832,7 +1832,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* The second argument of pointer_plus must be interpreted as signed, and
thus sign-extended if necessary. */
(with { tree stype = signed_type_for (TREE_TYPE (@1)); }
(convert (convert:stype @1))))
/* Use view_convert instead of convert here, as POINTER_PLUS_EXPR
second arg is unsigned even when we need to consider it as signed,
we don't want to diagnose overflow here. */
(convert (view_convert:stype @1))))
/* (T)P - (T)(P + A) -> -(T) A */
(simplify
@ -1876,7 +1879,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* The second argument of pointer_plus must be interpreted as signed, and
thus sign-extended if necessary. */
(with { tree stype = signed_type_for (TREE_TYPE (@1)); }
(negate (convert (convert:stype @1)))))
/* Use view_convert instead of convert here, as POINTER_PLUS_EXPR
second arg is unsigned even when we need to consider it as signed,
we don't want to diagnose overflow here. */
(negate (convert (view_convert:stype @1)))))
/* (T)(P + A) - (T)(P + B) -> (T)A - (T)B */
(simplify
@ -1927,7 +1933,11 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* The second argument of pointer_plus must be interpreted as signed, and
thus sign-extended if necessary. */
(with { tree stype = signed_type_for (TREE_TYPE (@1)); }
(minus (convert (convert:stype @1)) (convert (convert:stype @2)))))))
/* Use view_convert instead of convert here, as POINTER_PLUS_EXPR
second arg is unsigned even when we need to consider it as signed,
we don't want to diagnose overflow here. */
(minus (convert (view_convert:stype @1))
(convert (view_convert:stype @2)))))))
/* Simplifications of MIN_EXPR, MAX_EXPR, fmin() and fmax(). */

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2018-01-18 Jakub Jelinek <jakub@redhat.com>
PR c/61240
* gcc.dg/pr61240.c: New test.
2018-01-17 Harald Anlauf <anlauf@gmx.de>
PR fortran/83864

20
gcc/testsuite/gcc.dg/pr61240.c Normal file
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@ -0,0 +1,20 @@
/* PR c/61240 */
/* { dg-do compile } */
typedef __PTRDIFF_TYPE__ ptrdiff_t;
ptrdiff_t
foo (ptrdiff_t a[4])
{
int i[4];
int *p = i + 2;
static ptrdiff_t b = p - (p - 1); /* { dg-bogus "integer overflow in expression" } */
static ptrdiff_t c = (p - 1) - p; /* { dg-bogus "integer overflow in expression" } */
static ptrdiff_t d = (p - 2) - (p - 1);/* { dg-bogus "integer overflow in expression" } */
static ptrdiff_t e = (p - 1) - (p - 2);/* { dg-bogus "integer overflow in expression" } */
a[0] = p - (p - 1); /* { dg-bogus "integer overflow in expression" } */
a[1] = (p - 1) - p; /* { dg-bogus "integer overflow in expression" } */
a[2] = (p - 2) - (p - 1); /* { dg-bogus "integer overflow in expression" } */
a[3] = (p - 1) - (p - 2); /* { dg-bogus "integer overflow in expression" } */
return b + c + d + e;
}