Joseph, Richard, this is patch implementing the ENUM/INGEGER globbing and also POINTER/REFERENCE (though I don't know if that one follows by some standard rules). Joseph, does the attached testcase make sense for you? Is it defined? It is my first attempt to really interpret C standard to detail.
Ideally I would like to have testcases for all the globbing we do and reasoning why it is needed. Bootstraped/regtested ppc64le-linux. OK? Honza * lto.c (hash_canonical_type): Use tree_code_for_canonical_type_merging. * tree.h (tree_code_for_canonical_type_merging): New function. * tree.c (gimple_canonical_types_compatible_p): Use tree_code_for_canonical_type_merging.. * gcc.dg/lto/c-compatible-types_0.c: New testcase. * gcc.dg/lto/c-compatible-types_1.c: New testcase. Index: lto/lto.c =================================================================== --- lto/lto.c (revision 223877) +++ lto/lto.c (working copy) @@ -319,7 +319,7 @@ smaller sets; when searching for existing matching types to merge, only existing types having the same features as the new type will be checked. */ - hstate.add_int (TREE_CODE (type)); + hstate.add_int (tree_code_for_canonical_type_merging (TREE_CODE (type))); hstate.add_int (TYPE_MODE (type)); /* Incorporate common features of numerical types. */ Index: testsuite/gcc.dg/lto/c-compatible-types_0.c =================================================================== --- testsuite/gcc.dg/lto/c-compatible-types_0.c (revision 0) +++ testsuite/gcc.dg/lto/c-compatible-types_0.c (working copy) @@ -0,0 +1,21 @@ +/* { dg-do run } */ +/* { dg-options "-O3" } */ +/* By C standard Each enumerated type shall be compatible with char, a signed + integer, type, or an unsigned integer type. The choice of type is + implementation-defined. Check that enum and unsigned int match. */ +unsigned int a; +unsigned int *b; +void t(); + +void reset () +{ + asm("":"=r"(a):"0"(0)); +} +int +main() +{ + asm("":"=r"(a):"0"(1)); + asm("":"=r"(b):"0"(&a)); + t(); + return 0; +} Index: testsuite/gcc.dg/lto/c-compatible-types_1.c =================================================================== --- testsuite/gcc.dg/lto/c-compatible-types_1.c (revision 0) +++ testsuite/gcc.dg/lto/c-compatible-types_1.c (working copy) @@ -0,0 +1,19 @@ +enum a {test1, test2}; +enum a a; +enum a *b; + +void reset (void); + +void +t() +{ + if (a != test2) + __builtin_abort (); + if (*b != test2) + __builtin_abort (); + reset (); + if (a != test1) + __builtin_abort (); + if (*b != test1) + __builtin_abort (); +} Index: tree.c =================================================================== --- tree.c (revision 223877) +++ tree.c (working copy) @@ -12877,7 +12877,8 @@ return TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2); /* Can't be the same type if the types don't have the same code. */ - if (TREE_CODE (t1) != TREE_CODE (t2)) + if (tree_code_for_canonical_type_merging (TREE_CODE (t1)) + != tree_code_for_canonical_type_merging (TREE_CODE (t2))) return false; /* Qualifiers do not matter for canonical type comparison purposes. */ Index: tree.h =================================================================== --- tree.h (revision 223877) +++ tree.h (working copy) @@ -4598,7 +4598,28 @@ extern void DEBUG_FUNCTION verify_type (const_tree t); extern bool gimple_canonical_types_compatible_p (const_tree, const_tree, bool trust_type_canonical = true); +/* Return simplified tree code of type that is used for canonical type merging. */ +inline enum tree_code +tree_code_for_canonical_type_merging (enum tree_code code) +{ + /* By C standard, each enumerated type shall be compatible with char, + a signed integer, or an unsigned integer. The choice of type is + implementation defined (in our case it depends on -fshort-enum). + For this reason we make no distinction between ENUMERAL_TYPE and INTEGER + type and compare only by their signedness and precision. */ + if (code == ENUMERAL_TYPE) + return INTEGER_TYPE; + /* To allow inter-operability between languages having references and + C, we consider reference types and pointers alike. Note that this is + not strictly necessary for C-Fortran 2008 interoperability because + Fortran define C_PTR type that needs to be compatible with C pointers + and we handle this one as ptr_type_node. */ + if (code == REFERENCE_TYPE) + return POINTER_TYPE; + return code; +} + #define tree_map_eq tree_map_base_eq extern unsigned int tree_map_hash (const void *); #define tree_map_marked_p tree_map_base_marked_p