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PR middle-end/97556 - ICE on excessively large index into a multidimensional array

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gcc/ChangeLog:

	PR middle-end/97556
	* builtins.c (access_ref::add_offset): Cap offset lower bound
	to at most the the upper bound.

gcc/testsuite/ChangeLog:

	PR middle-end/97556
	* gcc.dg/Warray-bounds-70.c: New test.
This commit is contained in:
Martin Sebor 2020-10-30 13:04:29 -06:00
parent f3ced6772e
commit bdf6524bc0
2 changed files with 25 additions and 1 deletions
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8
gcc/builtins.c
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@ -321,7 +321,13 @@ void access_ref::add_offset (const offset_int &min, const offset_int &max)
offrng[1] = maxoff;
offset_int absmax = wi::abs (max);
if (offrng[0] < absmax)
offrng[0] += min;
{
offrng[0] += min;
/* Cap the lower bound at the upper (set to MAXOFF above)
to avoid inadvertently recreating an inverted range. */
if (offrng[1] < offrng[0])
offrng[0] = offrng[1];
}
else
offrng[0] = 0;
}

18
gcc/testsuite/gcc.dg/Warray-bounds-70.c Normal file
View File

@ -0,0 +1,18 @@
/* PR middle-end/97556 - ICE on excessively large index into a multidimensional
array
{ dg-do compile }
{ dg-options "-O2 -Wall" } */
#define SIZE_MAX __SIZE_MAX__
typedef __SIZE_TYPE__ size_t;
char a[1][3];
void f (int c)
{
size_t i = c ? SIZE_MAX / 2 : SIZE_MAX;
a[i][0] = 0; // { dg-warning "\\\[-Warray-bounds" }
}
// { dg-prune-output "\\\[-Wstringop-overflow=" }