https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62212
Bug ID: 62212 Summary: ICE compiling template function with array reference parameter whose size depends on a template parameter Product: gcc Version: 4.9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: lhyatt at gmail dot com I get an ICE in gcc 4.8.1 and also on 4.9 when compiling the code below. Doesn't matter the optimization level or what -std=: ============================ typedef int my_int; template<typename T> struct X { enum {value = 1}; }; template<typename T> void f(const my_int(&)[X<T>::value]); int main() { const my_int a[1] = {}; f<void>(a); } ============================ $ g++ -v -c t.cpp Using built-in specs. COLLECT_GCC=/usr/local/gcc48/bin/g++ Target: x86_64-unknown-linux-gnu Configured with: ./configure --enable-threads=posix --enable-__cxa_atexit --prefix=/usr/local/gcc-4.8.1 Thread model: posix gcc version 4.8.1 (GCC) COLLECT_GCC_OPTIONS='-v' '-c' '-shared-libgcc' '-mtune=generic' '-march=x86-64' /usr/local/gcc-4.8.1/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/cc1plus -quiet -v -D_GNU_SOURCE t.cpp -quiet -dumpbase t.cpp -mtune=generic -march=x86-64 -auxbase t -version -o /tmp/ccbr6RST.s GNU C++ (GCC) version 4.8.1 (x86_64-unknown-linux-gnu) compiled by GNU C version 4.8.1, GMP version 4.3.2, MPFR version 2.4.2-p1, MPC version 0.8.1 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 ignoring nonexistent directory "/usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../x86_64-unknown-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1 /usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1/x86_64-unknown-linux-gnu /usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/../../../../include/c++/4.8.1/backward /usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/include /usr/local/include /usr/local/gcc-4.8.1/include /usr/local/gcc-4.8.1/lib/gcc/x86_64-unknown-linux-gnu/4.8.1/include-fixed /usr/include End of search list. GNU C++ (GCC) version 4.8.1 (x86_64-unknown-linux-gnu) compiled by GNU C version 4.8.1, GMP version 4.3.2, MPFR version 2.4.2-p1, MPC version 0.8.1 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 9381368e685e312c931bb6a2db2d568c t.cpp: In instantiation of 'void f(const my_int (&)[X<T>::value]) [with T = void; my_int = int]': t.cpp:13:15: required from here t.cpp:9:6: internal compiler error: Segmentation fault void f(const my_int(&)[X<T>::value]); ^ 0x89ffef crash_signal ../.././gcc/toplev.c:332 0x72a8c7 fold_convert_loc(unsigned int, tree_node*, tree_node*) ../.././gcc/fold-const.c:1879 0x72e648 associate_trees ../.././gcc/fold-const.c:891 0x71d534 fold_binary_loc(unsigned int, tree_code, tree_node*, tree_node*, tree_node*) ../.././gcc/fold-const.c:10589 0x72768a fold_build2_stat_loc(unsigned int, tree_code, tree_node*, tree_node*, tree_node*) ../.././gcc/fold-const.c:14877 0x7195ce fold_binary_loc(unsigned int, tree_code, tree_node*, tree_node*, tree_node*) ../.././gcc/fold-const.c:9934 0x72768a fold_build2_stat_loc(unsigned int, tree_code, tree_node*, tree_node*, tree_node*) ../.././gcc/fold-const.c:14877 0x89ac30 layout_type(tree_node*) ../.././gcc/stor-layout.c:2230 0xa0aaa3 build_array_type_1 ../.././gcc/tree.c:7490 0x5add1f build_cplus_array_type(tree_node*, tree_node*) ../.././gcc/cp/tree.c:811 0x5af08e cp_build_qualified_type_real(tree_node*, int, int) ../.././gcc/cp/tree.c:1000 0x5bd2a0 canonicalize_for_substitution ../.././gcc/cp/mangle.c:364 0x5bd2a0 write_type ../.././gcc/cp/mangle.c:1886 0x5bd61d write_type ../.././gcc/cp/mangle.c:2052 0x5be6ff write_method_parms ../.././gcc/cp/mangle.c:2496 0x5be7fd write_bare_function_type ../.././gcc/cp/mangle.c:2438 0x5bbaff write_mangled_name ../.././gcc/cp/mangle.c:689 0x5c145d mangle_decl_string ../.././gcc/cp/mangle.c:3431 0x5c15d8 get_mangled_id ../.././gcc/cp/mangle.c:3453 0x5c15d8 mangle_decl(tree_node*) ../.././gcc/cp/mangle.c:3476 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions. ============================ It seems to be related to "my_int" being a typedef... if you change it to #define my_int int then it works fine. Also, if I intentionally give it the wrong sort of array, then it gives the correct error message and does not ICE, e.g. if I change the type to "const double a[1] = {}" then i get: t.cpp: In function 'int main()': t.cpp:13:14: error: no matching function for call to 'f(const double [1])' f<void>(a); ^ t.cpp:13:14: note: candidate is: t.cpp:9:6: note: template<class T> void f(const my_int (&)[X<T>::value]) void f(const my_int(&)[X<T>::value]); ^ t.cpp:9:6: note: template argument deduction/substitution failed: t.cpp:13:14: note: cannot convert 'a' (type 'const double [1]') to type 'const my_int (&)[1] {aka const int (&)[1]}' f<void>(a); And similarly if I make the array the wrong size, larger than expected, it also gives the correct error. But when the parameter matches, and the type in the declaration of f is a typedef, then I get the ICE. Thanks! -lewis