On Wed, 15 Feb 2017, Prathamesh Kulkarni wrote:
> Hi,
> For the following (invalid) test-case:
>
> void __GIMPLE () foo (int a)
> {
> int t0;
> int _1;
> _1 = a;
> t0_1 = a;
> }
>
> results in following ICE:
> gimplefe-error-4.c: In function ‘foo’:
> gimplefe-error-4.c:20:1: error: SSA_NAME_DEF_STMT is wrong
> }
> ^
> Expected definition statement:
> _1 = a_2(D);
>
> Actual definition statement:
> _1 = a_2(D);
> gimplefe-error-4.c:20:1: internal compiler error: verify_ssa failed
> 0xe1458b verify_ssa(bool, bool)
> ../../gcc/gcc/tree-ssa.c:1184
> 0xb0d1ed execute_function_todo
> ../../gcc/gcc/passes.c:1973
> 0xb0dad5 execute_todo
> ../../gcc/gcc/passes.c:2016
>
> The reason for ICE is that in c_parser_parse_ssa_name, ssa_name (1)
> returns tree node for _1, and "t0_1" gets replaced by "_1"
> resulting in multiple definitions for _1.
>
> The attached patch checks if multiple ssa names have same version
> number and emits a diagnostic in that case, for the above case:
> gimplefe-error-4.c: In function ‘foo’:
> gimplefe-error-4.c:10:3: error: ssa version ‘1’ used anonymously and in ‘t0’
> t0_1 = a;
> ^~~~
>
> OK to commit after bootstrap+test ?
Hmm, I'd rather (if at all -- I consider these kind of verification errors
appropriate for valid GIMPLE FE input) do sth like
Index: gcc/c/gimple-parser.c
===================================================================
--- gcc/c/gimple-parser.c (revision 245501)
+++ gcc/c/gimple-parser.c (working copy)
@@ -315,6 +315,12 @@ c_parser_gimple_statement (c_parser *par
else if (! FLOAT_TYPE_P (TREE_TYPE (lhs.value))
&& FLOAT_TYPE_P (TREE_TYPE (rhs.value)))
code = FIX_TRUNC_EXPR;
+ if (TREE_CODE (lhs.value) == SSA_NAME
+ && SSA_NAME_DEF_STMT (lhs.value))
+ {
+ c_parser_error (parser, "duplicate definition of SSA name");
+ /* point at previous definition, do not emit stmt */
+ }
assign = gimple_build_assign (lhs.value, code, rhs.value);
gimple_seq_add_stmt (seq, assign);
gimple_set_location (assign, loc);
@@ -347,6 +353,13 @@ c_parser_gimple_statement (c_parser *par
rhs = c_parser_gimple_unary_expression (parser);
if (rhs.value != error_mark_node)
{
+ if (TREE_CODE (lhs.value) == SSA_NAME
+ && SSA_NAME_DEF_STMT (lhs.value))
+ {
+ c_parser_error (parser, "duplicate definition of SSA name");
+ /* point at previous definition, do not emit stmt */
+ }
+
assign = gimple_build_assign (lhs.value, rhs.value);
gimple_set_location (assign, loc);
gimple_seq_add_stmt (seq, assign);
@@ -420,6 +433,13 @@ c_parser_gimple_statement (c_parser *par
if (lhs.value != error_mark_node
&& rhs.value != error_mark_node)
{
+ if (TREE_CODE (lhs.value) == SSA_NAME
+ && SSA_NAME_DEF_STMT (lhs.value))
+ {
+ c_parser_error (parser, "duplicate definition of SSA name");
+ /* point at previous definition, do not emit stmt */
+ }
+
assign = gimple_build_assign (lhs.value, rhs.value);
gimple_seq_add_stmt (seq, assign);
gimple_set_location (assign, loc);
@@ -692,8 +712,7 @@ c_parser_parse_ssa_name (c_parser *parse
if (VECTOR_TYPE_P (TREE_TYPE (parent))
|| TREE_CODE (TREE_TYPE (parent)) == COMPLEX_TYPE)
DECL_GIMPLE_REG_P (parent) = 1;
- name = make_ssa_name_fn (cfun, parent,
- gimple_build_nop (), version);
+ name = make_ssa_name_fn (cfun, parent, NULL, version);
}
}
basically at the point we emit a SSA def diagnose existing ones.
Should be split out into a verify_def () function, and the diagnostic
should be more helpful of course.
Richard.
>
> Thanks,
> Prathamesh
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
