On 05/18/2018 12:15 PM, Martin Sebor wrote: > Under some apparently rare conditions a DECL can have a non- > constant size that the fix for bug 85753 committed last week > into trunk was not prepared for. The attached change removes > the assumption to avoid the ICE that otherwise results. > > Martin > > PS The test case that triggers the ICE makes use of variable- > length structs and local functions, both of which are fairly > obscure GCC extensions that I tend to forget to consider when > writing GCC code. I tried to construct a less convoluted (and > strictly conforming) test case but in all of those I've come > up with a variable-length object is represented by a pointer > (pointing to memory returned by __builtin_alloca_with_align()). > Is there a straightforward way to create a variable-size DECL > that doesn't rely on GCC extensions? I think creating a type of a variable size, then an object of that type is the key. So a type with a flexible array/vla. Which is precisely what your test does.
For the most part DECL_SIZE comes from TYPE_SIZE. See layout_decl. > > gcc-85826.diff > > > PR tree-optimization/85826 - ICE in gimple-ssa-warn-restruct on a > variable-length struct > > gcc/ChangeLog: > > PR tree-optimization/85826 > * gimple-ssa-warn-restrict.c (builtin_memref::builtin_memref): Avoid > assuming that a DECL necesarily has a constant size. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/85826 > * gcc.dg/Wrestrict-17.c: New test. OK. jeff
