[Bug c/106582] New: Wrong code generation resulting in HardFault

["jankowski938 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106582

            Bug ID: 106582
           Summary: Wrong code generation resulting in HardFault
           Product: gcc
           Version: 10.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jankowski938 at gmail dot com
  Target Milestone: ---

It makes -Ofast, -O3 unusable.


1154                                    pQueryChunk->pSrcDriver =
pParser->pSourceDriver;
080157f4:   ldr.w   r3, [r9, #20]
080157f8:   str.w   r3, [r11, #12]
080157fc:   b.n     0x801556e <httpG4WebPage+1130>
080157fe:   movs    r3, #0
08015800:   ldr.w   r2, [r9, #20]
08015804:   str     r2, [r3, #12]
08015806:   udf     #255    ; 0xff   <---------- obviously wrong


                        if (pQueryChunk && ioIsValid(pRawChunk))
                        {
                                pQueryChunk->pSrcDriver =
pRawChunk->pSrcDriver;
                        }                       
                        else if (pParser)
                        {
                                pQueryChunk->pSrcDriver =
pParser->pSourceDriver;
                        }


GNU C11 (GNU Tools for STM32 10.3-2021.10.20211105-1100) version 10.3.1
20210824 (release) (arm-none-eabi)
        compiled by GNU C version 7.3-win32 20180312, GMP version 6.1.0, MPFR
version 3.1.4, MPC version 1.0.3, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
COLLECT_GCC_OPTIONS='-mcpu=cortex-m4' '-std=gnu11' '-g3' '-D' '_GNU_SOURCE=1'
'-D' 'USE_HAL_DRIVER' '-D' '_DEBUG=1' '-D' 'DEBUG_RUN_WITHOUT_CHECKS=1' '-D'
'DEBUGFILEWRITE=0' '-D' 'DEBUG=0' '-D' 'SLOWSPIDEBUG=0' '-D' 'USE_FULL_ASSERT'
'-D' '__USE_SIMPLE_SWO=0' '-D' 'USE_SWOTRACE=1' '-D' 'AMD64' '-D'
'HSE_VALUE=16000000UL' '-D' 'USE_FULL_LL_DRIVER=0' '-D' 'BOOTLOADER_VERSION=1'
'-D' 'ALLOW_SOFTWARE_BKPTS=1' '-D' 'ARM_MATH_CM4' '-D' 'FORCE_CUBE_USB' '-D'
'USE_EMBEDDED_PHY=1' '-D' 'USE_USB_OTG_FS=1' '-D' 'BITMAP_LCD_ALLOWED=0' '-D'
'LCDGUI_ALLOWED=0' '-D' 'LCD_ALLOWED=0' '-D' 'GPS_ALLOWED=0' '-D' 'STM32L4S9xx'
'-D' 'STM32L' '-D' 'INCLUDE_SLEEP_FUNCTIONS=1' '-D' 'COMPILE_FOR_EWB=1' '-D'
'COMPILE_USE_PL4S=1' '-c' '-Ofast' '-ffunction-sections' '-fdata-sections'
'-Wall' '-v' '-fstack-usage' '-MMD' '-MP' '-MF' '-MT'  '-specs=nano.specs'
'-mfpu=fpv4-sp-d16' '-mfloat-abi=hard' '-mthumb' '-o'  '-mlibarch=armv7e-m+fp'
'-march=armv7e-m+fp'
 -march=armv7e-m -mfloat-abi=hard -mfpu=fpv4-sp-d16 -meabi=5 -o
Libraries/STM32L4xx_HAL_Driver/Src/stm32l4xx_hal_pwr.o
C:\Users\Piotr\AppData\Local\Temp\ccHP5ygN.s
GNU assembler version 2.36.1 (arm-none-eabi) using BFD version (GNU Tools for
STM32 10.3-2021.10.20211105-1100) 2.36.1.20210621