[Bug tree-optimization/14841] [tree-ssa] const_array[CST] is not folded

["steven at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From steven at gcc dot gnu dot org  2004-08-13 00:04 -------
Given your test case, 
 
(gdb) set args -O2 t.c 
(gdb) b fold if (current_function_decl != (tree*)0) 
Breakpoint 5 at 0x658717: file ../../mainline/gcc/fold-const.c, line 6018. 
(gdb) run 
Starting program: /space/stevenb/build/gcc/cc1 -O2 t.c 
Breakpoint 3 at 0x2a9569d9c0 
Breakpoint 4 at 0x2a9569c750 
 foo 
 
Breakpoint 5, fold (expr=0x2a95905f80) at ../../mainline/gcc/fold-const.c:6018 
6018      const tree t = expr; 
(gdb) p debug_generic_expr (expr) 
banana<D1464>[2] 
$2 = void 
(gdb) p debug_tree(expr) 
 <array_ref 0x2a95905f80 
    type <integer_type 0x2a955978c0 int SI 
        size <integer_cst 0x2a95595780 constant invariant 32> 
        unit size <integer_cst 0x2a955958d0 constant invariant 4> 
        align 32 symtab 0 alias set -1 precision 32 min <integer_cst 
0x2a95595870 -2147483648> max <integer_cst 0x2a955958a0 2147483647> 
        pointer_to_this <pointer_type 0x2a955a8540>> 
    readonly 
    arg 0 <var_decl 0x2a95901ee0 banana 
        type <array_type 0x2a95901e00 type <integer_type 0x2a9562ec40 int> 
            BLK 
            size <integer_cst 0x2a95595de0 constant invariant 128> 
            unit size <integer_cst 0x2a9559f4b0 constant invariant 16> 
            align 32 symtab 0 alias set -1 domain <integer_type 0x2a95629a80>> 
        readonly used static BLK file t.c line 1 size <integer_cst 
0x2a95595de0 128> unit size <integer_cst 0x2a9559f4b0 16> 
        align 32 initial <constructor 0x2a9562c080>> 
    arg 1 <integer_cst 0x2a95913f30 type <integer_type 0x2a955978c0 int> 
constant invariant 2>> 
$3 = void 
(gdb) p debug_tree ((tree *)0x2a9562c080) 
 <constructor 0x2a9562c080 
    type <array_type 0x2a95901e00 
        type <integer_type 0x2a9562ec40 int readonly SI 
            size <integer_cst 0x2a95595780 constant invariant 32> 
            unit size <integer_cst 0x2a955958d0 constant invariant 4> 
            align 32 symtab 0 alias set -1 precision 32 min <integer_cst 
0x2a95595870 -2147483648> max <integer_cst 0x2a955958a0 2147483647> 
            pointer_to_this <pointer_type 0x2a9562ed20>> 
        BLK 
        size <integer_cst 0x2a95595de0 constant invariant 128> 
        unit size <integer_cst 0x2a9559f4b0 constant invariant 16> 
        align 32 symtab 0 alias set -1 
        domain <integer_type 0x2a95629a80 type <integer_type 0x2a955a6700 long 
unsigned int> 
            DI 
            size <integer_cst 0x2a95595900 constant invariant 64> 
            unit size <integer_cst 0x2a95595a50 constant invariant 8> 
            align 64 symtab 0 alias set -1 precision 64 min <integer_cst 
0x2a9559f5d0 0> max <integer_cst 0x2a95628000 3>>> 
    constant invariant static 
    arg 0 <tree_list 0x2a959139f0 
        purpose <integer_cst 0x2a959139c0 constant invariant 0> 
        value <integer_cst 0x2a95913990 constant invariant 0> 
        chain <tree_list 0x2a95913a80 
            purpose <integer_cst 0x2a95913a50 constant invariant 1> 
            value <integer_cst 0x2a95913a20 constant invariant 1> 
            chain <tree_list 0x2a95913b10 
                purpose <integer_cst 0x2a95913ae0 constant invariant 2> 
                value <integer_cst 0x2a95913ab0 constant invariant 2> 
                chain <tree_list 0x2a95913bd0 
                    purpose <integer_cst 0x2a95913ba0 constant invariant 3> 
                    value <integer_cst 0x2a95913b70 constant invariant 3>>>>>> 
$4 = void 
(gdb) 
 
So somebody should just teach fold-const to fold ARRAY_REFs to 
readonly memory. 
 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14841