https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127534
Bug ID: 127534
Summary: [GIMPLE FE] SSA names accepted where they are not
valid: as ARRAY_REF base, in a non-SSA body, or
without a definition
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: ice-on-invalid-code
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: captainnemo9292 at gmail dot com
Target Milestone: ---
Target: x86_64-linux-gnu
Three related holes in how the GIMPLE parser handles names of the form x_N:
1. An SSA name used as the base of an array reference. The parser builds
a_10[0] as an ARRAY_REF with an SSA_NAME base (instead of requiring
__MEM), and the operand scanner asserts:
void __GIMPLE (ssa) b(int *a) {
__BB(2):
a_10[0] = 0;
}
$ gcc -fgimple -c t.c
internal compiler error: in get_expr_operands, at tree-ssa-operands.cc:943
operands_scanner::get_expr_operands <- parse_ssa_operands <-
build_ssa_operands <- update_stmt_operands <- c_parser_parse_gimple_body
https://godbolt.org/z/r6hq3z41c
2. An SSA-style name in a body that is not in SSA form. a_10 is created
with no usable type and build2 is called with mismatched operand types:
void __GIMPLE b(int *a) {
int c; int d;
a_10 = c + d;
}
internal compiler error: in build2, at tree.cc:5312
https://godbolt.org/z/v4aPfs7M8
3. A use of an SSA version that is never defined; update_ssa runs on the
half-built function:
void __GIMPLE (ssa) a() {
int i;
__BB(3):
i = i_1;
goto __BB4;
__BB(4):
}
internal compiler error: SSA corruption
update_ssa <- c_parser_parse_gimple_body
https://godbolt.org/z/fP5Mreo4e
gcc trunk 17.0.0 20260920.
