| Message ID | 20180129181257.GG2620@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | C++ PATCH to fix a crash in cxx_fold_indirect_ref (PR c++/83996) | expand |
OK. On Mon, Jan 29, 2018 at 1:12 PM, Marek Polacek <polacek@redhat.com> wrote: > The crash here is caused by size_binop_loc getting operands of different types: > sizetype and ssizetype. Fixed by performing the computation in offset_int, > much as we do in fold_indirect_ref_1 (fixed in middle-end/81695). > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > 2018-01-29 Marek Polacek <polacek@redhat.com> > > PR c++/83996 > * constexpr.c (cxx_fold_indirect_ref): Compute ((foo *)&fooarray)[1] > => fooarray[1] in offset_int. > > * g++.dg/ext/pr83996.C: New test. > > diff --git gcc/cp/constexpr.c gcc/cp/constexpr.c > index 4d2ee4a28fc..0a1944f6dad 100644 > --- gcc/cp/constexpr.c > +++ gcc/cp/constexpr.c > @@ -3143,11 +3143,17 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) > 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); > + offset_int off = wi::to_offset (op01); > + offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); > + offset_int remainder; > + off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); > + if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) > + { > + off = off + wi::to_offset (min_val); > + op01 = wide_int_to_tree (sizetype, off); > + return build4_loc (loc, ARRAY_REF, type, op00, op01, > + NULL_TREE, NULL_TREE); > + } > } > /* Also handle conversion to an empty base class, which > is represented with a NOP_EXPR. */ > diff --git gcc/testsuite/g++.dg/ext/pr83996.C gcc/testsuite/g++.dg/ext/pr83996.C > index e69de29bb2d..e663d728349 100644 > --- gcc/testsuite/g++.dg/ext/pr83996.C > +++ gcc/testsuite/g++.dg/ext/pr83996.C > @@ -0,0 +1,11 @@ > +// PR c++/83996 > +// { dg-do compile } > +// { dg-options "" } > + > +int z[] = { }; > + > +int > +main (void) > +{ > + __builtin_printf ("%d\n", *(z + 1)); > +} > > Marek
diff --git gcc/cp/constexpr.c gcc/cp/constexpr.c index 4d2ee4a28fc..0a1944f6dad 100644 --- gcc/cp/constexpr.c +++ gcc/cp/constexpr.c @@ -3143,11 +3143,17 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) 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); + offset_int off = wi::to_offset (op01); + offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); + offset_int remainder; + off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); + if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) + { + off = off + wi::to_offset (min_val); + op01 = wide_int_to_tree (sizetype, off); + return build4_loc (loc, ARRAY_REF, type, op00, op01, + NULL_TREE, NULL_TREE); + } } /* Also handle conversion to an empty base class, which is represented with a NOP_EXPR. */ diff --git gcc/testsuite/g++.dg/ext/pr83996.C gcc/testsuite/g++.dg/ext/pr83996.C index e69de29bb2d..e663d728349 100644 --- gcc/testsuite/g++.dg/ext/pr83996.C +++ gcc/testsuite/g++.dg/ext/pr83996.C @@ -0,0 +1,11 @@ +// PR c++/83996 +// { dg-do compile } +// { dg-options "" } + +int z[] = { }; + +int +main (void) +{ + __builtin_printf ("%d\n", *(z + 1)); +}