I just tried to compile the Linux kernel 2.6.33-rc6 under valgrind with the C compiler version 4.5 snapshot 20100128 and valgrind said
==2968== Conditional jump or move depends on uninitialised value(s) ==2968== at 0x7A6925: delegitimize_mem_from_attrs (simplify-rtx.c:244) ==2968== by 0x961517: ix86_delegitimize_address (i386.c:10883) ==2968== by 0x93E5F6: emit_note_insn_var_location (var-tracking.c:6515) ==2968== by 0xCB84D7: htab_traverse_noresize (hashtab.c:753) ==2968== by 0x941376: emit_notes_for_changes (var-tracking.c:6741) ==2968== by 0x946A67: vt_emit_notes (var-tracking.c:7106) ==2968== by 0x94A602: variable_tracking_main (var-tracking.c:7637) ==2968== by 0x722ECA: execute_one_pass (passes.c:1561) ==2968== by 0x723154: execute_pass_list (passes.c:1616) ==2968== by 0x723166: execute_pass_list (passes.c:1617) ==2968== by 0x723166: execute_pass_list (passes.c:1617) ==2968== by 0x818C94: tree_rest_of_compilation (tree-optimize.c:413) ==2968== Line 244 of simplify-rtx.c is if (bitsize != GET_MODE_BITSIZE (mode) || (bitpos % BITS_PER_UNIT) || (toffset && !host_integerp (toffset, 0))) decl = NULL; Preprocessed source code attached. Flags -Os -g required. -- Summary: simplify-rtx.c:244: Conditional jump or move depends on uninitialised value(s) Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: dcb314 at hotmail dot com GCC host triplet: x86_64-suse-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42993