https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86518
Bug ID: 86518
Summary: Strengthen bootstrap comparison by not enabling
warnings at stage3
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: bootstrap
Assignee: unassigned at gcc dot gnu.org
Reporter: amonakov at gcc dot gnu.org
Target Milestone: ---
Currently stage2 and 3 use the same warning options, but that is redundant: if
any warnings are generated, they will be present at stage2 (and stop
bootstrap). By not enabling any warnings for stage3, we would get checking that
warnings do not affect code generation.
Note that simply adding -w at stage3 doesn't work, as it simply suppresses the
warning at print time.
I tried leaving only -Wno-narrowing in warning flags and got many comparison
failures:
Comparing stages 2 and 3
warning: gcc/cc1obj-checksum.o differs
Bootstrap comparison failure!
gcc/calls.o differs
gcc/dwarf2out.o differs
gcc/loop-iv.o differs
gcc/generic-match.o differs
gcc/ipa-inline.o differs
gcc/builtins.o differs
gcc/optabs.o differs
gcc/tree-vrp.o differs
gcc/profile.o differs
gcc/i386.o differs
gcc/cfgexpand.o differs
gcc/simplify-rtx.o differs
gcc/gimple-ssa-sprintf.o differs
gcc/expr.o differs
gcc/print-tree.o differs
gcc/gimple-match.o differs
gcc/godump.o differs
gcc/gimple-ssa-nonnull-compare.o differs
gcc/targhooks.o differs
gcc/tree-ssa-live.o differs
gcc/gimple-ssa-warn-restrict.o differs
gcc/tree-ssa-ccp.o differs
gcc/gimplify.o differs
gcc/tree-cfg.o differs
gcc/tree-pretty-print.o differs
make: *** [compare] Error 1
