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[Bug bootstrap/80887] gnat bootstrap fails at s-regpat.o: raised STORAGE_ERROR : stack overflow or erroneous memory access
- From: "glisse at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 26 May 2017 21:38:43 +0000
- Subject: [Bug bootstrap/80887] gnat bootstrap fails at s-regpat.o: raised STORAGE_ERROR : stack overflow or erroneous memory access
- Auto-submitted: auto-generated
- References: <bug-80887-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80887
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> ---
Seems to me that it is FRE valueization doing something strange. We have (not
in a loop)
_26 = CHAIN.23_25(D)->parse_pos;
_28 = _26 + 1;
CHAIN.23_25(D)->parse_pos = _28;
_30 = CHAIN.23_25(D)->expression;
_32 = _30->P_ARRAY;
_33 = CHAIN.23_25(D)->parse_pos;
parse_pos.11_2 = (sizetype) _33;
_3 = parse_pos.11_2 + 4294967295;
and when, during the simplification of some later stmt that turns out to be
equivalent to _3, we call vn_nary_op_lookup_pieces on _26 (with a NOP to
sizetype), it returns _3, so obviously we loop.