On Tue, Apr 30, 2024 at 1:06 AM Roger Sayle <ro...@nextmovesoftware.com> wrote: > > > This patch solves another ICE-after-error problem in the C family > front-ends. Upon a conflicting type redeclaration, the ambiguous > type is poisoned with an error_mark_node to indicate to the middle-end > that the type is suspect, but care has to be taken by the front-end to > avoid passing these malformed trees into the middle-end during error > recovery. In this case, a var_decl with a poisoned type appears within > a sizeof() expression (wrapped in NOP_EXPR) which causes problems. > > This revision of the patch tests seen_error() to avoid tree traversal > (STRIP_NOPs) in the most common case that an error hasn't occurred. > Both this version (and an earlier revision that didn't test seen_error) > have survived bootstrap and regression testing on x86_64-pc-linux-gnu. > As a consolation, this code also contains a minor performance improvement, > by avoiding trying to create (and folding away) a CEIL_DIV_EXPR in the > common case that "char" is a single-byte. The current code relies on > the middle-end's tree folding to recognize that CEIL_DIV_EXPR of > integer_one_node is a no-op, that can be optimized away. > > Ok for mainline?
Where does it end up ICEing? I see size_binop_loc guards against error_mark_node operands already, maybe it should use error_operand_p instead? > > 2024-04-30 Roger Sayle <ro...@nextmovesoftware.com> > > gcc/c-family/ChangeLog > PR c/109618 > * c-common.cc (c_sizeof_or_alignof_type): If seen_error() check > whether value is (a VAR_DECL) of type error_mark_node, or a > NOP_EXPR thereof. Avoid folding CEIL_DIV_EXPR for the common > case where char_type is a single byte. > > gcc/testsuite/ChangeLog > PR c/109618 > * gcc.dg/pr109618.c: New test case. > > > Thanks in advance, > Roger > -- >
