[Bug sanitizer/68587] New: [6 Regression][UBSAN] ICE in expand_insn, at optabs.c:6974

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68587

            Bug ID: 68587
           Summary: [6 Regression][UBSAN] ICE in expand_insn, at
                    optabs.c:6974
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org
  Target Milestone: ---

Created attachment 36857
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36857&action=edit
test.ii, compile with: g++ -Ofast -fsanitize=undefined

Very recently, GCC 6 compiled the big program - since today it fails with an
ICE.

Compile the reduced program with:
  g++ -Ofast -fsanitize=undefined -S test.ii


It fails here with:

test27.ii: In member function âint MSMeasurement::compareWithGrid(const
MSMeasurement&, const ECoordinate&, const ECoordinate&) constâ:
test27.ii:128:28: internal compiler error: in expand_insn, at optabs.c:6974
         double fa=floor(a/g);
                            ^

0xc2c143 expand_insn(insn_code, unsigned int, expand_operand*)
        ../../gcc/optabs.c:6974
0xb026a4 expand_direct_optab_fn
        ../../gcc/internal-fn.c:2147
0x91c69a expand_call_stmt
        ../../gcc/cfgexpand.c:2565
0x91c69a expand_gimple_stmt_1
        ../../gcc/cfgexpand.c:3525
0x91c69a expand_gimple_stmt
        ../../gcc/cfgexpand.c:3688
0x91f25a expand_gimple_basic_block
        ../../gcc/cfgexpand.c:5694
0x924b46 execute
        ../../gcc/cfgexpand.c:6309