Date:   Tue, 5 Apr 2022 12:04:59 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Richard Biener <rguenther@...e.de>
Cc:     linux-toolchains@...r.kernel.org, Michael Matz <matz@...e.de>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: older gccs and case labels producing integer constants

On Tue, Apr 05, 2022 at 11:58:33AM +0200, Richard Biener wrote:
> also with 'unsigned int i' but that's accepted with GCC 7.  So
> what do you switch on?

Ah, right, so it must be some of the gazillion switches. Below's a dump
from building the asm version of that same file.

Can you recognize which one might be causing this?

# GNU C11 (SUSE Linux) version 7.5.0 (x86_64-suse-linux)
#       compiled by GNU C version 7.5.0, GMP version 6.1.2, MPFR version 4.0.2-p6, MPC version 1.1.0, isl version isl-0.18-GMP

# GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
# options passed:  -nostdinc -I ./arch/x86/include
# -I ./arch/x86/include/generated -I ./include -I ./arch/x86/include/uapi
# -I ./arch/x86/include/generated/uapi -I ./include/uapi
# -I ./include/generated/uapi -D __KERNEL__ -D CC_USING_FENTRY -D MODULE
# -D KBUILD_BASENAME="midi" -D KBUILD_MODNAME="snd_usbmidi_lib"
# -D __KBUILD_MODNAME=kmod_snd_usbmidi_lib
# -include ./include/linux/compiler-version.h
# -include ./include/linux/kconfig.h
# -include ./include/linux/compiler_types.h -MMD sound/usb/.midi.s.d
# sound/usb/midi.c -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -m64
# -mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3
# -mskip-rax-setup -mtune=generic -mno-red-zone -mcmodel=kernel
# -mindirect-branch=thunk-extern -mindirect-branch-register -mrecord-mcount
# -mfentry -march=x86-64 -auxbase-strip sound/usb/midi.s -O2 -Wall -Wundef
# -Werror=strict-prototypes -Wno-trigraphs
# -Werror=implicit-function-declaration -Werror=implicit-int
# -Werror=return-type -Wno-format-security -Wno-sign-compare
# -Wno-frame-address -Wformat-truncation=0 -Wformat-overflow=0
# -Wframe-larger-than=2048 -Werror -Wimplicit-fallthrough=5 -Wno-main
# -Wno-unused-but-set-variable -Wunused-const-variable=0
# -Wdeclaration-after-statement -Wvla -Wno-pointer-sign
# -Wstringop-overflow=0 -Wno-restrict -Wno-maybe-uninitialized
# -Werror=date-time -Werror=incompatible-pointer-types
# -Werror=designated-init -std=gnu11 -p -fno-strict-aliasing -fno-common
# -fshort-wchar -fno-PIE -falign-jumps=1 -falign-loops=1
# -fno-asynchronous-unwind-tables -fno-jump-tables
# -fno-delete-null-pointer-checks -fno-reorder-blocks -fno-ipa-cp-clone
# -fno-partial-inlining -fstack-protector-strong
# -fno-stack-clash-protection -fno-inline-functions-called-once
# -falign-functions=64 -fno-strict-overflow -fstack-check=no
# -fconserve-stack -fsanitize=bounds -fsanitize=shift
# -fsanitize=integer-divide-by-zero -fsanitize=bool -fsanitize=enum
# -fsanitize-coverage=trace-pc -fverbose-asm
# --param allow-store-data-races=0
# options enabled:  -falign-labels -fauto-inc-dec -fbranch-count-reg
# -fcaller-saves -fchkp-check-incomplete-type -fchkp-check-read
# -fchkp-check-write -fchkp-instrument-calls -fchkp-narrow-bounds
# -fchkp-optimize -fchkp-store-bounds -fchkp-use-static-bounds
# -fchkp-use-static-const-bounds -fchkp-use-wrappers -fcode-hoisting
# -fcombine-stack-adjustments -fcompare-elim -fcprop-registers
# -fcrossjumping -fcse-follow-jumps -fdefer-pop -fdevirtualize
# -fdevirtualize-speculatively -fdwarf2-cfi-asm -fearly-inlining
# -feliminate-unused-debug-types -fexpensive-optimizations
# -fforward-propagate -ffp-int-builtin-inexact -ffunction-cse -fgcse
# -fgcse-lm -fgnu-runtime -fgnu-unique -fguess-branch-probability
# -fhoist-adjacent-loads -fident -fif-conversion -fif-conversion2
# -findirect-inlining -finline -finline-atomics -finline-small-functions
# -fipa-bit-cp -fipa-cp -fipa-icf -fipa-icf-functions -fipa-icf-variables
# -fipa-profile -fipa-pure-const -fipa-reference
# -fipa-reference-addressable -fipa-sra -fipa-stack-alignment -fipa-vrp
# -fira-hoist-pressure -fira-share-save-slots -fira-share-spill-slots
# -fisolate-erroneous-paths-dereference -fivopts -fkeep-static-consts
# -fleading-underscore -flifetime-dse -flra-remat -flto-odr-type-merging
# -fmath-errno -fmerge-constants -fmerge-debug-strings
# -fmove-loop-invariants -fomit-frame-pointer -foptimize-sibling-calls
# -foptimize-strlen -fpeephole -fpeephole2 -fplt -fprefetch-loop-arrays
# -fprofile -free -freg-struct-return -freorder-functions
# -frerun-cse-after-loop -fsanitize-coverage=trace-pc
# -fsched-critical-path-heuristic -fsched-dep-count-heuristic
# -fsched-group-heuristic -fsched-interblock -fsched-last-insn-heuristic
# -fsched-rank-heuristic -fsched-spec -fsched-spec-insn-heuristic
# -fsched-stalled-insns-dep -fschedule-fusion -fschedule-insns2
# -fsemantic-interposition -fshow-column -fshrink-wrap
# -fshrink-wrap-separate -fsigned-zeros -fsplit-ivs-in-unroller
# -fsplit-wide-types -fssa-backprop -fssa-phiopt -fstack-protector-strong
# -fstdarg-opt -fstore-merging -fstrict-volatile-bitfields -fsync-libcalls
# -fthread-jumps -ftoplevel-reorder -ftrapping-math -ftree-bit-ccp
# -ftree-builtin-call-dce -ftree-ccp -ftree-ch -ftree-coalesce-vars
# -ftree-copy-prop -ftree-cselim -ftree-dce -ftree-dominator-opts
# -ftree-dse -ftree-forwprop -ftree-fre -ftree-loop-if-convert
# -ftree-loop-im -ftree-loop-ivcanon -ftree-loop-optimize
# -ftree-parallelize-loops= -ftree-phiprop -ftree-pre -ftree-pta
# -ftree-reassoc -ftree-scev-cprop -ftree-sink -ftree-slsr -ftree-sra
# -ftree-switch-conversion -ftree-tail-merge -ftree-ter -ftree-vrp
# -funit-at-a-time -fverbose-asm -fzero-initialized-in-bss
# -m128bit-long-double -m64 -malign-stringops -mavx256-split-unaligned-load
# -mavx256-split-unaligned-store -mfentry -mfxsr -mglibc -mieee-fp
# -mindirect-branch-register -mlong-double-80 -mno-fancy-math-387
# -mno-red-zone -mno-sse4 -mpush-args -mrecord-mcount -mskip-rax-setup
# -mtls-direct-seg-refs -mvzeroupper

-- 
Regards/Gruss,
    Boris.

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