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re PR c/83844 (ICE with warn_if_not_aligned attribute)

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PR c/83844
	* stor-layout.c (handle_warn_if_not_align): Use byte_position and
	multiple_of_p instead of unchecked tree_to_uhwi and UHWI check.
	If off is not INTEGER_CST, issue a may not be aligned warning
	rather than isn't aligned.  Use isn%'t rather than isn't.
	* fold-const.c (multiple_of_p) <case BIT_AND_EXPR>: Don't fall through
	into MULT_EXPR.
	<case MULT_EXPR>: Improve the case when bottom and one of the
	MULT_EXPR operands are INTEGER_CSTs and bottom is multiple of that
	operand, in that case check if the other operand is multiple of
	bottom divided by the INTEGER_CST operand.

	* gcc.dg/pr83844.c: New test.

From-SVN: r256745
This commit is contained in:
Jakub Jelinek 2018-01-16 16:08:32 +01:00 committed by Jakub Jelinek
parent 42b394ff00
commit 38943500ba
5 changed files with 91 additions and 7 deletions
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14
gcc/ChangeLog
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@ -1,3 +1,17 @@
2018-01-16 Jakub Jelinek <jakub@redhat.com>
PR c/83844
* stor-layout.c (handle_warn_if_not_align): Use byte_position and
multiple_of_p instead of unchecked tree_to_uhwi and UHWI check.
If off is not INTEGER_CST, issue a may not be aligned warning
rather than isn't aligned. Use isn%'t rather than isn't.
* fold-const.c (multiple_of_p) <case BIT_AND_EXPR>: Don't fall through
into MULT_EXPR.
<case MULT_EXPR>: Improve the case when bottom and one of the
MULT_EXPR operands are INTEGER_CSTs and bottom is multiple of that
operand, in that case check if the other operand is multiple of
bottom divided by the INTEGER_CST operand.
2018-01-16 Richard Sandiford <richard.sandiford@linaro.org>
PR target/83858

27
gcc/fold-const.c
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@ -12595,9 +12595,34 @@ multiple_of_p (tree type, const_tree top, const_tree bottom)
a multiple of BOTTOM then TOP is a multiple of BOTTOM. */
if (!integer_pow2p (bottom))
return 0;
/* FALLTHRU */
return (multiple_of_p (type, TREE_OPERAND (top, 1), bottom)
|| multiple_of_p (type, TREE_OPERAND (top, 0), bottom));
case MULT_EXPR:
if (TREE_CODE (bottom) == INTEGER_CST)
{
op1 = TREE_OPERAND (top, 0);
op2 = TREE_OPERAND (top, 1);
if (TREE_CODE (op1) == INTEGER_CST)
std::swap (op1, op2);
if (TREE_CODE (op2) == INTEGER_CST)
{
if (multiple_of_p (type, op2, bottom))
return 1;
/* Handle multiple_of_p ((x * 2 + 2) * 4, 8). */
if (multiple_of_p (type, bottom, op2))
{
widest_int w = wi::sdiv_trunc (wi::to_widest (bottom),
wi::to_widest (op2));
if (wi::fits_to_tree_p (w, TREE_TYPE (bottom)))
{
op2 = wide_int_to_tree (TREE_TYPE (bottom), w);
return multiple_of_p (type, op1, op2);
}
}
return multiple_of_p (type, op1, bottom);
}
}
return (multiple_of_p (type, TREE_OPERAND (top, 1), bottom)
|| multiple_of_p (type, TREE_OPERAND (top, 0), bottom));

16
gcc/stor-layout.c
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@ -1150,12 +1150,16 @@ handle_warn_if_not_align (tree field, unsigned int record_align)
warning (opt_w, "alignment %u of %qT is less than %u",
record_align, context, warn_if_not_align);
unsigned HOST_WIDE_INT off
= (tree_to_uhwi (DECL_FIELD_OFFSET (field))
+ tree_to_uhwi (DECL_FIELD_BIT_OFFSET (field)) / BITS_PER_UNIT);
if ((off % warn_if_not_align) != 0)
warning (opt_w, "%q+D offset %wu in %qT isn't aligned to %u",
field, off, context, warn_if_not_align);
tree off = byte_position (field);
if (!multiple_of_p (TREE_TYPE (off), off, size_int (warn_if_not_align)))
{
if (TREE_CODE (off) == INTEGER_CST)
warning (opt_w, "%q+D offset %E in %qT isn%'t aligned to %u",
field, off, context, warn_if_not_align);
else
warning (opt_w, "%q+D offset %E in %qT may not be aligned to %u",
field, off, context, warn_if_not_align);
}
}
/* Called from place_field to handle unions. */

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2018-01-16 Jakub Jelinek <jakub@redhat.com>
PR c/83844
* gcc.dg/pr83844.c: New test.
2018-01-16 Richard Sandiford <richard.sandiford@linaro.org>
* gcc.dg/torture/pr83847.c: New test.

36
gcc/testsuite/gcc.dg/pr83844.c Normal file
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@ -0,0 +1,36 @@
/* PR c/83844 */
/* { dg-do compile } */
/* { dg-options "-O0 -Wall" } */
typedef unsigned long long __u64 __attribute__((aligned(4),warn_if_not_aligned(8)));
void bar (void *, void *, void *);
void
foo (int n)
{
struct A
{
int i1;
int i2;
int i3[n];
__u64 x; /* { dg-warning "in 'struct A' may not be aligned to 8" } */
} __attribute__((aligned (8)));
struct B
{
int i1;
int i2;
long long i3[n];
__u64 x;
} __attribute__((aligned (8)));
struct C
{
int i1;
int i2;
int i3[2 * n];
__u64 x;
} __attribute__((aligned (8)));
struct A a;
struct B b;
struct C c;
bar (&a, &b, &c);
}