| Summary: | aliasing problem | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Fabien Douze <fabdouze> |
| Component: | rtl-optimization | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | normal | CC: | gcc-bugs |
| Priority: | P2 | ||
| Version: | 3.2.2 | ||
| Target Milestone: | 3.4.0 | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | ||
There is only one: "An object shall have its stored value accessed only by an lvalue expression that has one of the following types: -- a type compatible with the effective type of the object, -- a qualified version of a type compatible with the effective type of the object, -- a type that is the signed or unsigned type corresponding to the effective type of the object, -- a type that is the signed or unsigned type corresponding to a qualified version of the effective type of the object, -- an aggregate or union type that includes one of the aforementioned types among its members (including, recursively, a member of a subaggregate or contained union), or -- a character type." and this is exactly the one you are violating, since you're accessing struct _LSPESn as STC. Reopening to ... |
I have the following code typedef struct _LSPESn { struct _LSPESn *esnext; /* next ES neighbour in LSP chain */ X esdefm; /* ES neighbour default metric */ X esdlym; /* ES neighbour delay metric */ X esexpm; /* ES neighbour expense metric */ X eserrm; /* ES neighbour error metric */ X esid[LGSYSID]; /* ES neighbour system ID */ } LSPESnT, *LSPESnTp; typedef struct STC { struct STC *stnext ; } ST, *STp; LSPESnTp es2, esn; for ( esn = ent->lspesn ; 0!=esn ; esn = es2 ) { es2 = esn->esnext; (((STp)( (STp)esn ))->stnext) = ( &(((SATenTp)( E2Ispp ))->sat_i2i. fr eeLspESn ) )->prp_first; ( & (((SATenTp)( E2Ispp ))->sat_i2i.reeLspESn ) )->prp_first = ((STp)( (STp)esn )); ; } It causes an infinit loop when compiling with -O2 option. Apperently, gcc considere esn->esnext and (((STp)( (STp)esn ))->stnext) as two different memory area and skip es2 in the generated library. Isn't it a gcc bug? It seems to be the same case than in bug 9902. But I do not see which aliasing rules is not respected. Thanks, Fabien