https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97615
Bug ID: 97615
Summary: [11 Regression] -O3 on -Wsequence-point-unclean code
ICEs: during GIMPLE pass: slp: internal compiler
error: in vectorizable_live_operation, at
tree-vect-loop.c:8497
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: slyfox at gcc dot gnu.org
Target Milestone: ---
Host: x86_64-pc-linux-gnu
The ICE initially observed on dolphin-emu code base. cvise reduced it down to
the following example:
$ cat bug.cpp
// g++-11.0.0 -O3 -std=c++17 -c bug.cpp -o bug.o -Wall
short *a;
void b(int c, int d) {
*a++ = *a++ = c;
*a++ = d;
}
int e, f;
void g() {
b(e + f - 2, e + f - 1);
b(e + f - 1, 0);
}
gcc crashes as:
$ LANG=C g++-11.0.0 -O3 -c bug.cpp -o bug.o -Wall
bug.cpp: In function 'void b(int, int)':
bug.cpp:4:5: warning: operation on 'a' may be undefined [-Wsequence-point]
4 | *a++ = *a++ = c;
| ~^~
during GIMPLE pass: slp
bug.cpp: In function 'void g()':
bug.cpp:8:6: internal compiler error: in vectorizable_live_operation, at
tree-vect-loop.c:8497
8 | void g() {
| ^
0x60f1cb vectorizable_live_operation(vec_info*, _stmt_vec_info*,
gimple_stmt_iterator*, _slp_tree*, _slp_instance*, int, bool,
vec<stmt_info_for_cost, va_heap, vl_ptr>*)
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-loop.c:8497
0xe82bd7 can_vectorize_live_stmts
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-stmts.c:10529
0xea4f58 vect_transform_stmt(vec_info*, _stmt_vec_info*, gimple_stmt_iterator*,
_slp_tree*, _slp_instance*)
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-stmts.c:10913
0xed1611 vect_schedule_slp_node
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:5360
0xedd1cf vect_schedule_scc
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:5495
0xedd8fc vect_schedule_slp(vec_info*, vec<_slp_instance*, va_heap, vl_ptr>)
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:5624
0xeded4b vect_slp_region
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:4232
0xeded4b vect_slp_bbs
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:4350
0xedfb3c vect_slp_function(function*)
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vect-slp.c:4418
0xee1923 execute
/usr/src/debug/sys-devel/gcc-11.0.0_pre9999/gcc-11.0.0_pre9999/gcc/tree-vectorizer.c:1437
