Re: [GIMPLE FE] Avoid ICE with __builtin_abs

[Richard Biener <rguenther at suse dot de>]

On Sat, 4 Feb 2017, Prathamesh Kulkarni wrote:

> Hi,
> The following test-case ICE's with -fgimple:
> 
> int __GIMPLE foo(int a)
> {
>   int t1;
>   t1_1 = __builtin_abs (a);
>   return t1_1;
> }
> 
> gimplefe-2.c:4:3: internal compiler error: in get_callee_fndecl, at tree.c:9500
>    t1_1 = __builtin_abs (a);
>    ^~~~
> 0xe96e8d get_callee_fndecl(tree_node const*)
> ../../gcc/gcc/tree.c:9500
> 0x924d75 gimple_build_call_from_tree(tree_node*)
> ../../gcc/gcc/gimple.c:351
> 0x6c86b3 c_parser_gimple_statement
> ../../gcc/gcc/c/gimple-parser.c:393
> 0x6c86b3 c_parser_gimple_compound_statement
> ../../gcc/gcc/c/gimple-parser.c:216
> 0x6c86b3 c_parser_parse_gimple_body(c_parser*)
> ../../gcc/gcc/c/gimple-parser.c:93
> 0x6b04f1 c_parser_declaration_or_fndef
> ../../gcc/gcc/c/c-parser.c:2081
> 0x6b883b c_parser_external_declaration
> ../../gcc/gcc/c/c-parser.c:1464
> 0x6b92a1 c_parser_translation_unit
> ../../gcc/gcc/c/c-parser.c:1344
> 0x6b92a1 c_parse_file()
> ../../gcc/gcc/c/c-parser.c:18141
> 0x717832 c_common_parse_file()
> ../../gcc/gcc/c-family/c-opts.c:1102
> 
> This happens because __builtin_abs(a) gets folded to <nop_expr<abs_expr<a>>
> and get_callee_fndecl expects CALL_EXPR.
> 
> The attached patch tries to fix the issue by building gimple_assign
> with appropriate subcode
> for functions that get folded to expression instead of trying to build
> it as a function-call.
> Is it OK to commit after bootstrap+test ?

No.  The proper fix is to not use the C frontend call-expr parsing
and building -- it does have many more issues I think.

Richard.

> Thanks,
> Prathamesh
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)