https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71549
Bug ID: 71549 Summary: ICE on valid code at -O2 and -O3 with -g enabled in 64-bit mode on x86_64-linux-gnu: in simplify_subreg, at simplify-rtx.c:5952 Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- The following code causes an ICE when compiled with the current gcc trunk at -O2 and -O3 with -g enabled on x86_64-linux-gnu in the 64-bit mode (but not in the 32-bit mode). It is a regression from 6.1.x. $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160615 (experimental) [trunk revision 237485] (GCC) $ $ gcc-trunk -m64 -Os -g small.c $ gcc-6.1 -m64 -O2 -g small.c $ $ gcc-trunk -m64 -O2 -g small.c small.c: In function ‘main’: small.c:21:1: internal compiler error: in simplify_subreg, at simplify-rtx.c:5952 } ^ 0xba9fab simplify_subreg(machine_mode, rtx_def*, machine_mode, unsigned int) ../../gcc-source-trunk/gcc/simplify-rtx.c:5951 0xbaa5c9 simplify_gen_subreg(machine_mode, rtx_def*, machine_mode, unsigned int) ../../gcc-source-trunk/gcc/simplify-rtx.c:6171 0xeab2db vt_expand_loc_callback ../../gcc-source-trunk/gcc/var-tracking.c:8435 0x7e9b59 cselib_expand_value_rtx_1 ../../gcc-source-trunk/gcc/cselib.c:1648 0x7eb53e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def* (*)(rtx_def*, bitmap_head*, int, void*), void*) ../../gcc-source-trunk/gcc/cselib.c:1530 0xeab763 vt_expand_var_loc_chain ../../gcc-source-trunk/gcc/var-tracking.c:8330 0xeab763 vt_expand_loc_callback ../../gcc-source-trunk/gcc/var-tracking.c:8492 0x7e9a75 cselib_expand_value_rtx_1 ../../gcc-source-trunk/gcc/cselib.c:1683 0x7eb53e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def* (*)(rtx_def*, bitmap_head*, int, void*), void*) ../../gcc-source-trunk/gcc/cselib.c:1530 0xeab763 vt_expand_var_loc_chain ../../gcc-source-trunk/gcc/var-tracking.c:8330 0xeab763 vt_expand_loc_callback ../../gcc-source-trunk/gcc/var-tracking.c:8492 0x7eb53e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def* (*)(rtx_def*, bitmap_head*, int, void*), void*) ../../gcc-source-trunk/gcc/cselib.c:1530 0xeab763 vt_expand_var_loc_chain ../../gcc-source-trunk/gcc/var-tracking.c:8330 0xeab763 vt_expand_loc_callback ../../gcc-source-trunk/gcc/var-tracking.c:8492 0x7e9a75 cselib_expand_value_rtx_1 ../../gcc-source-trunk/gcc/cselib.c:1683 0x7eb53e cselib_expand_value_rtx_cb(rtx_def*, bitmap_head*, int, rtx_def* (*)(rtx_def*, bitmap_head*, int, void*), void*) ../../gcc-source-trunk/gcc/cselib.c:1530 0xeaa359 vt_expand_var_loc_chain ../../gcc-source-trunk/gcc/var-tracking.c:8330 0xeaa359 vt_expand_1pvar ../../gcc-source-trunk/gcc/var-tracking.c:8605 0xeaa359 emit_note_insn_var_location(variable**, emit_note_data*) ../../gcc-source-trunk/gcc/var-tracking.c:8660 0xead3da traverse_noresize<emit_note_data*, emit_note_insn_var_location> ../../gcc-source-trunk/gcc/hash-table.h:950 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. $ -------------------------- struct S1 { int f0; int f1; int f2; int:4; } a, b; void fn1 (struct S1 p1) { a = p1; int c = p1.f0; } int main () { fn1 (b); return 0; }