[Bug tree-optimization/104655] New: [12 Regression] array subscript 0 is outside array bounds of

[Bug tree-optimization/104655] New: [12 Regression] array subscript 0 is outside array bounds of

[pmenzel+gcc at molgen dot mpg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

            Bug ID: 104655
           Summary: [12 Regression] array subscript 0 is outside array
                    bounds of
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pmenzel+gcc at molgen dot mpg.de
  Target Milestone: ---

Building SeaBIOS and coreboot with GCC 12 from Debian sid/unstable

    gcc-12 (Debian 12-20220222-1) 12.0.1 20220222 (experimental) [master
r12-7325-g2f59f067610]

new warnings and errors are shown.

SeaBIOS (commit 829b0f1 (nvme: fix LBA format data structure)):

```
  Compile checking out/src/optionroms.o
In function 'boot_irq_captured',
    inlined from 'init_pcirom' at src/optionroms.c:344:28:
src/optionroms.c:314:25: warning: array subscript 0 is outside array bounds of
'struct segoff_s[0]' [-Warray-bounds]
  314 |     return GET_IVT(0x19).segoff != FUNC16(entry_19_official).segoff;
In function 'boot_irq_captured',
    inlined from 'init_pcirom' at src/optionroms.c:348:9:
src/optionroms.c:314:25: warning: array subscript 0 is outside array bounds of
'struct segoff_s[0]' [-Warray-bounds]
  314 |     return GET_IVT(0x19).segoff != FUNC16(entry_19_official).segoff;
In file included from src/optionroms.c:10:
In function 'boot_irq_restore',
    inlined from 'init_pcirom' at src/optionroms.c:354:9:
src/farptr.h:182:35: warning: array subscript 0 is outside array bounds of
'struct segoff_s[0]' [-Warray-bounds]
  182 |     do { GET_FARVAR((seg), (var)) = (val); } while (0)
      |                                   ^
src/biosvar.h:22:5: note: in expansion of macro 'SET_FARVAR'
   22 |     SET_FARVAR(SEG_IVT, ((struct rmode_IVT *)0)->ivec[vector], segoff)
      |     ^~~~~~~~~~
src/optionroms.c:322:5: note: in expansion of macro 'SET_IVT'
  322 |     SET_IVT(0x19, seabios);
      |     ^~~~~~~
src/farptr.h:182:35: warning: array subscript 1 is outside array bounds of
'struct segoff_s[0]' [-Warray-bounds]
  182 |     do { GET_FARVAR((seg), (var)) = (val); } while (0)
      |                                   ^
src/biosvar.h:22:5: note: in expansion of macro 'SET_FARVAR'
   22 |     SET_FARVAR(SEG_IVT, ((struct rmode_IVT *)0)->ivec[vector], segoff)
      |     ^~~~~~~~~~
src/optionroms.c:322:5: note: in expansion of macro 'SET_IVT'
  322 |     SET_IVT(0x19, seabios);
      |     ^~~~~~~
```

(There are more of similar kind.)

coreboot (commit 5bba93e0 (mb/google/brya: Enable eMMC HS400 mode for nissa)),
and editing `util/xcompile/xcompile` to use GCC 12, building Asus F2A85-M PRO:

```
    CC        
libagesa/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatures.o
x86_64-linux-gnu-gcc-12 -MMD -Isrc -Isrc/include -Isrc/commonlib/include
-Isrc/commonlib/bsd/include -Ibuild -I3rdparty/vboot/firmware/include -include
src/include/kconfig.h -include src/include/rules.h -include
src/commonlib/bsd/include/commonlib/bsd/compiler.h -I3rdparty
-D__BUILD_DIR__=\"build\" -Isrc/soc/amd/common/block/include/
-Isrc/arch/x86/include -Isrc/southbridge/amd/agesa/hudson
-Isrc/vendorcode/amd/include -Isrc/vendorcode/amd/agesa/f15tn
-Isrc/vendorcode/amd/agesa/f15tn/../common
-Isrc/vendorcode/amd/agesa/f15tn/Include
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch                   
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Common               
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Common                   
-D__ARCH_x86_32__ -pipe -g -nostdinc -std=gnu11 -nostdlib -Wall -Wundef
-Wstrict-prototypes -Wmissing-prototypes -Wwrite-strings -Wredundant-decls
-Wno-trigraphs -Wimplicit-fallthrough -Wshadow -Wdate-time -Wtype-limits -Wvla
-Wdangling-else -fno-common -ffreestanding -fno-builtin -fomit-frame-pointer
-fstrict-aliasing -ffunction-sections -fdata-sections -fno-pie
-Wno-packed-not-aligned -fconserve-stack -Wnull-dereference -Wreturn-type
-Wlogical-op -Wduplicated-cond -Wno-unused-but-set-variable -Werror -Os
-Wno-address-of-packed-member -m32 -Wl,-b,elf32-i386 -Wl,-melf_i386 -m32 
-fuse-ld=bfd -fno-stack-protector -Wl,--build-id=none
-fno-delete-null-pointer-checks -Wlogical-op -march=i686 -mno-mmx
-march=k8-sse3 -mtune=k8-sse3 -fno-strict-aliasing -MT
build/libagesa/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatures.o
-D__LIBAGESA__ -fno-zero-initialized-in-bss -Isrc/vendorcode/amd/include
-Isrc/vendorcode/amd/agesa/f15tn -Isrc/vendorcode/amd/agesa/f15tn/../common
-Isrc/vendorcode/amd/agesa/f15tn/Include -Isrc/vendorcode/amd/agesa/f15tn/Proc
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Tech
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Tech/DDR3
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps/TN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps/TN/FS1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps/TN/FP2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ps/TN/FM2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/NB
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/NB/TN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Main
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Main/TN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/TABLE
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/S3
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/PARTRN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/ODTHERMAL
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/MEMCLR
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/LVDDR3
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/INTLVRN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/IDENDIMM
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/EXCLUDIMM
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/ECC
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/DMI
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/CSINTLV
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/CRAT
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Feat/CHINTLV
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Mem/Ardk
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Perf
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Library
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Family/0x15
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Family/0x15/TN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Debug
-Isrc/vendorcode/amd/agesa/f15tn/Proc/IDS/Control
-Isrc/vendorcode/amd/agesa/f15tn/Proc/HT
-Isrc/vendorcode/amd/agesa/f15tn/Proc/HT/Fam15Mod1x
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbTable
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbSview
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbSbLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbSbIommuLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbSSocketLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieTrainingV1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieInitLibV4
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieInitLibV1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieConfig
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieClkPm
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieAspm
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbPcieAlibV1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbNbInitLibV4
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbNbInitLibV1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbMSocketLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbIvrsLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbIommuScratch
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbIommuIvrs
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbInitTN
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbGfxInitLibV1
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbGfxConfig
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbFamTranslation
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Modules/GnbCommonLib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Library
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Library/GnbTimerLibWrap0
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Include
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Include/Library
-Isrc/vendorcode/amd/agesa/f15tn/Proc/GNB/Common
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Usb
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Usb/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Usb/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Spi
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Spi/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Spi/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sd
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sd/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sd/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sata
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sata/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Sata/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Pcie
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Pcie/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Pcie/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Pcib
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Ir
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Interface
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Interface/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Interface/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Imc
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Imc/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Imc/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Ide
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Hwm
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Hwm/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Hwm/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/HwAcpi
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/HwAcpi/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/HwAcpi/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Gec
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Gec/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Gec/Family/Hudson2
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Common
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Fch/Azalia
-Isrc/vendorcode/amd/agesa/f15tn/Proc/Common
-Isrc/vendorcode/amd/agesa/f15tn/Proc/CPU
-Isrc/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature
-Isrc/vendorcode/amd/agesa/f15tn/Proc/CPU/Family
-Isrc/vendorcode/amd/agesa/f15tn/Proc/CPU/Family/0x15
-Isrc/vendorcode/amd/agesa/f15tn/Proc/CPU/Family/0x15/TN  -c -o
build/libagesa/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatures.o
src/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatures.c
src/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatureLeveling.c: In
function 'FeatureLeveling':
src/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatureLeveling.c:149:3:
error: array subscript 0 is outside array bounds of 'UINT64[0]' {aka 'long long
unsigned int[]'} [-Werror=array-bounds]
  149 |   *FirstTime = TRUE;
      |   ^~~~~~~~~~
src/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatureLeveling.c:150:3:
error: array subscript 0 is outside array bounds of 'UINT64[0]' {aka 'long long
unsigned int[]'} [-Werror=array-bounds]
  150 |   *NeedLeveling = FALSE;
      |   ^~~~~~~~~~~~~
src/vendorcode/amd/agesa/f15tn/Proc/CPU/Feature/cpuFeatureLeveling.c:171:7:
error: array subscript 0 is outside array bounds of 'UINT64[0]' {aka 'long long
unsigned int[]'} [-Werror=array-bounds]
  171 |   if (*NeedLeveling) {
      |       ^~~~~~~~~~~~~
```

QEMU i440fx fails too:

```
    CC         bootblock/cpu/x86/lapic/lapic.o
x86_64-linux-gnu-gcc-12 -MMD -Isrc -Isrc/include -Isrc/commonlib/include
-Isrc/commonlib/bsd/include -Ibuild -I3rdparty/vboot/firmware/include -include
src/include/kconfig.h -include src/include/rules.h -include
src/commonlib/bsd/include/commonlib/bsd/compiler.h -I3rdparty
-D__BUILD_DIR__=\"build\" -Isrc/arch/x86/include -D__ARCH_x86_32__ -pipe -g
-nostdinc -std=gnu11 -nostdlib -Wall -Wundef -Wstrict-prototypes
-Wmissing-prototypes -Wwrite-strings -Wredundant-decls -Wno-trigraphs
-Wimplicit-fallthrough -Wshadow -Wdate-time -Wtype-limits -Wvla -Wdangling-else
-fno-common -ffreestanding -fno-builtin -fomit-frame-pointer -fstrict-aliasing
-ffunction-sections -fdata-sections -fno-pie -Wno-packed-not-aligned
-fconserve-stack -Wnull-dereference -Wreturn-type -Wlogical-op
-Wduplicated-cond -Wno-unused-but-set-variable -Werror -Os
-Wno-address-of-packed-member -m32 -Wl,-b,elf32-i386 -Wl,-melf_i386 -m32 
-fuse-ld=bfd -fno-stack-protector -Wl,--build-id=none
-fno-delete-null-pointer-checks -Wlogical-op -march=i686 -mno-mmx -MT
build/bootblock/cpu/x86/lapic/lapic.o -D__BOOTBLOCK__ -c -o
build/bootblock/cpu/x86/lapic/lapic.o src/cpu/x86/lapic/lapic.c
In file included from src/include/cpu/x86/lapic.h:4,
                 from src/cpu/x86/lapic/lapic.c:5:
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_read' at src/include/cpu/x86/lapic.h:80:10,
    inlined from 'lapicid' at src/include/cpu/x86/lapic.h:138:21,
    inlined from 'enable_lapic' at src/cpu/x86/lapic/lapic.c:41:3:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:103:11,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:73:2:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'write32',
    inlined from 'xapic_write' at src/include/cpu/x86/lapic.h:18:2,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:106:3,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:73:2:
src/arch/x86/include/arch/mmio.h:40:40: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   40 |         *((volatile uint32_t *)(addr)) = value;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:103:11,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:77:2:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'write32',
    inlined from 'xapic_write' at src/include/cpu/x86/lapic.h:18:2,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:106:3,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:77:2:
src/arch/x86/include/arch/mmio.h:40:40: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   40 |         *((volatile uint32_t *)(addr)) = value;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:103:11,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:86:3:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'write32',
    inlined from 'xapic_write' at src/include/cpu/x86/lapic.h:18:2,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:106:3,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:86:3:
src/arch/x86/include/arch/mmio.h:40:40: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   40 |         *((volatile uint32_t *)(addr)) = value;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:103:11,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:84:3:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'write32',
    inlined from 'xapic_write' at src/include/cpu/x86/lapic.h:18:2,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:106:3,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:84:3:
src/arch/x86/include/arch/mmio.h:40:40: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   40 |         *((volatile uint32_t *)(addr)) = value;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
In function 'read32',
    inlined from 'xapic_read' at src/include/cpu/x86/lapic.h:13:9,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:103:11,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:89:2:
src/arch/x86/include/arch/mmio.h:20:16: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   20 |         return *((volatile uint32_t *)(addr));
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'write32',
    inlined from 'xapic_write' at src/include/cpu/x86/lapic.h:18:2,
    inlined from 'lapic_update32' at src/include/cpu/x86/lapic.h:106:3,
    inlined from 'setup_lapic_interrupts' at src/cpu/x86/lapic/lapic.c:89:2:
src/arch/x86/include/arch/mmio.h:40:40: error: array subscript 0 is outside
array bounds of 'const volatile void[0]' [-Werror=array-bounds]
   40 |         *((volatile uint32_t *)(addr)) = value;
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
```

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Can  you provide the preprocessed source in all cases?

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99578

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I am 90% sure this is just another dup of bug 99578.

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-02-23
             Status|UNCONFIRMED                 |WAITING
   Target Milestone|---                         |12.0
     Ever confirmed|0                           |1

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pmenzel+gcc at molgen dot mpg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

--- Comment #3 from Paul Menzel <pmenzel+gcc at molgen dot mpg.de> ---
(In reply to Andrew Pinski from comment #2)
> I am 90% sure this is just another dup of bug 99578.

Are you sure, because the warnings/errors are not there with GCC 11.

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
It is still very likely.
But if you provide what you are asked for we could know for sure.

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pmenzel+gcc at molgen dot mpg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

--- Comment #5 from Paul Menzel <pmenzel+gcc at molgen dot mpg.de> ---
Created attachment 52498
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52498&action=edit
Preprocessed file `build/bootblock/cpu/x86/lapic/lapic.i` with `-save-temps`

Sorry for not sharing the file in the first place. First for the coreboot case:

    $ x86_64-linux-gnu-gcc-12 -save-temps -MMD -Isrc -Isrc/include
-Isrc/commonlib/include -Isrc/commonlib/bsd/include -Ibuild
-I3rdparty/vboot/firmware/include -include src/include/kconfig.h -include
src/include/rules.h -include src/commonlib/bsd/include/commonlib/bsd/compiler.h
-I3rdparty -D__BUILD_DIR__=\"build\" -Isrc/arch/x86/include -D__ARCH_x86_32__
-pipe -g -nostdinc -std=gnu11 -nostdlib -Wall -Wundef -Wstrict-prototypes
-Wmissing-prototypes -Wwrite-strings -Wredundant-decls -Wno-trigraphs
-Wimplicit-fallthrough -Wshadow -Wdate-time -Wtype-limits -Wvla -Wdangling-else
-fno-common -ffreestanding -fno-builtin -fomit-frame-pointer -fstrict-aliasing
-ffunction-sections -fdata-sections -fno-pie -Wno-packed-not-aligned
-fconserve-stack -Wnull-dereference -Wreturn-type -Wlogical-op
-Wduplicated-cond -Wno-unused-but-set-variable -Werror -Os
-Wno-address-of-packed-member -m32 -Wl,-b,elf32-i386 -Wl,-melf_i386 -m32 
-fuse-ld=bfd -fno-stack-protector -Wl,--build-id=none
-fno-delete-null-pointer-checks -Wlogical-op -march=i686 -mno-mmx -MT
build/bootblock/cpu/x86/lapic/lapic.o -D__BOOTBLOCK__ -c -o
build/bootblock/cpu/x86/lapic/lapic.o src/cpu/x86/lapic/lapic.c

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Paul Menzel from comment #5)
> Created attachment 52498 [details]
> Preprocessed file `build/bootblock/cpu/x86/lapic/lapic.i` with `-save-temps`
> 
> Sorry for not sharing the file in the first place. First for the coreboot
> case:

This case is a dup of bug 99578.
lapicid:
 uint32_t lapicid = lapic_read(0x020);

static inline __attribute__((always_inline)) uint32_t lapic_read(unsigned int
reg)
{
 if (is_x2apic_mode())
  return x2apic_read(reg);
 else
  return xapic_read(reg);
}

static inline __attribute__((always_inline)) uint32_t xapic_read(unsigned int
reg)
{
 return read32((volatile void *)(uintptr_t)(0xfee00000 + reg));
}

static inline __attribute__((always_inline)) uint32_t read32(const volatile
void *addr)
{
 return *((volatile uint32_t *)(addr));
}

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[pmenzel+gcc at molgen dot mpg.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

--- Comment #7 from Paul Menzel <pmenzel+gcc at molgen dot mpg.de> ---
Thank you for the analysis. Excuse my ignorance, but the referenced bug
(possible dup) says it’s a regression in GCC 11, but it does not show up here
with GCC 11. Are more issues tracked in bug 99578?

[Bug tree-optimization/104655] [12 Regression] array subscript 0 is outside array bounds of

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104655

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |DUPLICATE
                 CC|                            |msebor at gcc dot gnu.org
             Status|WAITING                     |RESOLVED

--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> ---
The warning in the test case in comment #6 is intentional: it triggers because
the hardcoded address (0xfee00000) doesn't refer to a known object, same as in
the test case in bug 99578 comment 0.  The bug is still open because there's a
lack of consensus as to whether or how GCC should be enhanced to accept such
code without a warning.  -Warray-bounds and -Wstringop-overflow/-overread
depend on optimizations some of which tend to expose new instances of warnings
as optimizers improve from one release to another.

*** This bug has been marked as a duplicate of bug 99578 ***