https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116721
Bug ID: 116721 Summary: [15 Regression] ICE: in merge, at ipa-modref-tree.cc:176 Product: gcc Version: 15.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: ipa Assignee: unassigned at gcc dot gnu.org Reporter: patrick at rivosinc dot com Target Milestone: --- Testcase: short a, c; long b; void d(unsigned short e[][5]) { for (long f = 0; f < 1; f += b ?: c ?: -667603842056244355) a = 0 == 0 ? e[f][f] : 0; } Command/backtrace: > /scratch/tc-testing/tc-compiler-fuzz-trunk/build-gcv/bin/riscv64-unknown-linux-gnu-gcc > -O3 func.c -c -S -o /dev/null func.c: In function 'd': func.c:5:19: warning: iteration 3 invokes undefined behavior [-Waggressive-loop-optimizations] 5 | a = 0 == 0 ? e[f][f] : 0; | ^ func.c:4:22: note: within this loop 4 | for (long f = 0; f < 1; f += b ?: c ?: -667603842056244355) | ~~^~~ during GIMPLE pass: modref func.c:3:6: internal compiler error: in merge, at ipa-modref-tree.cc:176 3 | void d(unsigned short e[][5]) { | ^ 0x2e376e5 internal_error(char const*, ...) ../../../gcc/gcc/diagnostic-global-context.cc:517 0xc52bb0 fancy_abort(char const*, int, char const*) ../../../gcc/gcc/diagnostic.cc:1657 0xaae6ad modref_access_node::merge(modref_access_node const&, bool) ../../../gcc/gcc/ipa-modref-tree.cc:176 0x10f32d4 modref_access_node::try_merge_with(vec<modref_access_node, va_gc, vl_embed>*&, unsigned long) ../../../gcc/gcc/ipa-modref-tree.cc:457 0x10f513c modref_access_node::insert(vec<modref_access_node, va_gc, vl_embed>*&, modref_access_node, unsigned long, bool) ../../../gcc/gcc/ipa-modref-tree.cc:562 0x10efd83 modref_ref_node<int>::insert_access(modref_access_node, unsigned long, bool) ../../../gcc/gcc/ipa-modref-tree.h:194 0x10efd83 modref_tree<int>::insert(unsigned int, unsigned int, unsigned int, int, int, modref_access_node, bool) ../../../gcc/gcc/ipa-modref-tree.h:444 0x10e2358 modref_tree<int>::insert(tree_node*, int, int, modref_access_node const&, bool) ../../../gcc/gcc/ipa-modref-tree.h:471 0x10e2358 record_access ../../../gcc/gcc/ipa-modref.cc:1078 0x10e2ee8 analyze_load ../../../gcc/gcc/ipa-modref.cc:1715 0x1027c34 walk_stmt_load_store_addr_ops(gimple*, void*, bool (*)(gimple*, tree_node*, tree_node*, void*), bool (*)(gimple*, tree_node*, tree_node*, void*), bool (*)(gimple*, tree_node*, tree_node*, void*)) ../../../gcc/gcc/gimple-walk.cc:824 0x10e9381 analyze_stmt ../../../gcc/gcc/ipa-modref.cc:1796 0x10eabe9 analyze ../../../gcc/gcc/ipa-modref.cc:1908 0x10eabe9 analyze_function ../../../gcc/gcc/ipa-modref.cc:3233 0x10ec63e execute ../../../gcc/gcc/ipa-modref.cc:4254 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. Godbolt: https://godbolt.org/z/coYf1PzEd Tested with: riscv64-unknown-linux-gnu-gcc (gb56bd542942) 15.0.0 20240914 (experimental) Found via fuzzer.