| Message ID | 20170804083857.GC3397@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Aug 4, 2017 at 10:38 AM, Marek Polacek <polacek@redhat.com> wrote: > We were crashing because size_binop_loc got operands of different types: > sizetype and ssizetype. Richi suggested performing the computation in > offset_int which my patch tries to do. Unsure about the sdiv_trunc part, > what do I use instead of EXACT_DIV_EXPR? Use wi::divmod_trunc and check for a zero remainder. If the remainder is not zero we may not fold. Ok with that change. Thanks, Richard. > Bootstrapped/regtested on x86_64-linux, ok for trunk? Testing on ppc64le > in progress. > > 2017-08-04 Marek Polacek <polacek@redhat.com> > > PR middle-end/81695 > * fold-const.c (fold_indirect_ref_1): For ((int *)&a + 4 -> a[1], > perform the computation in offset_int. > > * gcc.dg/pr81695.c: New test. > > diff --git gcc/fold-const.c gcc/fold-const.c > index ed6c289a64b..64a84eb0197 100644 > --- gcc/fold-const.c > +++ gcc/fold-const.c > @@ -14106,14 +14106,17 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0) > && type == TREE_TYPE (op00type)) > { > tree type_domain = TYPE_DOMAIN (op00type); > - tree min_val = size_zero_node; > - if (type_domain && TYPE_MIN_VALUE (type_domain)) > - min_val = TYPE_MIN_VALUE (type_domain); > - op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, > - TYPE_SIZE_UNIT (type)); > - op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); > - return build4_loc (loc, ARRAY_REF, type, op00, op01, > - NULL_TREE, NULL_TREE); > + tree min = TYPE_MIN_VALUE (type_domain); > + if (min && TREE_CODE (min) == INTEGER_CST) > + { > + offset_int off = wi::to_offset (op01); > + offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); > + off = wi::sdiv_trunc (off, el_sz); > + off = off + wi::to_offset (min); > + op01 = wide_int_to_tree (sizetype, off); > + return build4_loc (loc, ARRAY_REF, type, op00, op01, > + NULL_TREE, NULL_TREE); > + } > } > } > } > diff --git gcc/testsuite/gcc.dg/pr81695.c gcc/testsuite/gcc.dg/pr81695.c > index e69de29bb2d..c3452580f1c 100644 > --- gcc/testsuite/gcc.dg/pr81695.c > +++ gcc/testsuite/gcc.dg/pr81695.c > @@ -0,0 +1,11 @@ > +/* PR middle-end/81695 */ > +/* { dg-do compile } */ > +/* { dg-options "" } */ > + > +int z[] = { }; > + > +int > +main (void) > +{ > + __builtin_printf ("%d\n", *(z + 1)); > +} > > Marek
diff --git gcc/fold-const.c gcc/fold-const.c index ed6c289a64b..64a84eb0197 100644 --- gcc/fold-const.c +++ gcc/fold-const.c @@ -14106,14 +14106,17 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0) && type == TREE_TYPE (op00type)) { tree type_domain = TYPE_DOMAIN (op00type); - tree min_val = size_zero_node; - if (type_domain && TYPE_MIN_VALUE (type_domain)) - min_val = TYPE_MIN_VALUE (type_domain); - op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, - TYPE_SIZE_UNIT (type)); - op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); - return build4_loc (loc, ARRAY_REF, type, op00, op01, - NULL_TREE, NULL_TREE); + tree min = TYPE_MIN_VALUE (type_domain); + if (min && TREE_CODE (min) == INTEGER_CST) + { + offset_int off = wi::to_offset (op01); + offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); + off = wi::sdiv_trunc (off, el_sz); + off = off + wi::to_offset (min); + op01 = wide_int_to_tree (sizetype, off); + return build4_loc (loc, ARRAY_REF, type, op00, op01, + NULL_TREE, NULL_TREE); + } } } } diff --git gcc/testsuite/gcc.dg/pr81695.c gcc/testsuite/gcc.dg/pr81695.c index e69de29bb2d..c3452580f1c 100644 --- gcc/testsuite/gcc.dg/pr81695.c +++ gcc/testsuite/gcc.dg/pr81695.c @@ -0,0 +1,11 @@ +/* PR middle-end/81695 */ +/* { dg-do compile } */ +/* { dg-options "" } */ + +int z[] = { }; + +int +main (void) +{ + __builtin_printf ("%d\n", *(z + 1)); +}