https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84985
Bug ID: 84985 Summary: internal compiler error: in match_reload, at lra-constraints.c:1068 Product: gcc Version: 8.0.1 Status: UNCONFIRMED Keywords: ice-on-invalid-code Severity: normal Priority: P3 Component: inline-asm Assignee: unassigned at gcc dot gnu.org Reporter: vegard.nossum at oracle dot com Target Milestone: --- Input: int main() { int a; asm("" : "=d"(a) : "0"(a), "0ae"(&a)); } Output: $ cc1plus int main() Analyzing compilation unit Performing interprocedural optimizations <*free_lang_data> <visibility> <build_ssa_passes> <opt_local_passes> <targetclone> <free-fnsummary> <whole-program> <fnsummary> <inline> <free-fnsummary> <single-use> <comdats>Assembling functions: <materialize-all-clones> <simdclone> int main()during RTL pass: reload <stdin>: In function 'int main()': <stdin>:4:1: internal compiler error: in match_reload, at lra-constraints.c:1068 0x287e277 match_reload /home/vegard/git/gcc/gcc/lra-constraints.c:1066 0x28ade79 curr_insn_transform /home/vegard/git/gcc/gcc/lra-constraints.c:4335 0x28b93b6 lra_constraints(bool) /home/vegard/git/gcc/gcc/lra-constraints.c:4877 0x2829984 lra(_IO_FILE*) /home/vegard/git/gcc/gcc/lra.c:2419 0x2608794 do_reload /home/vegard/git/gcc/gcc/ira.c:5465 0x2608794 execute /home/vegard/git/gcc/gcc/ira.c:5649 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. Version: GNU C++14 (GCC) version 8.0.1 20180306 (experimental) (x86_64-pc-linux-gnu) 7.3.0 seems to handle it and outputs: main: pushq %rbp movq %rsp, %rbp movl -4(%rbp), %eax leaq -4(%rbp), %rcx movl %eax, %edx movl %edx, %eax movl %eax, -4(%rbp) movl $0, %eax popq %rbp ret Clang says: <source>:3:36: error: more than one input constraint matches the same output '0' asm("" : "=d"(a) : "0"(a), "0ae"(&a)); ^ <source>:3:26: note: constraint '0' is already present here asm("" : "=d"(a) : "0"(a), "0ae"(&a)); ^ 1 error generated. Compiler returned: 1