On Fri, 2023-06-02 at 12:32 +0530, Senthil Kumar Selvaraj wrote: > On Mon, 2023-05-22 at 14:05 +0200, Richard Biener wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the > > content is safe > > > > On Fri, May 19, 2023 at 7:58 AM <senthilkumar.selva...@microchip.com> wrote: > > > On 26/04/23, 5:51 PM, "Richard Biener" <richard.guent...@gmail.com > > > <mailto:richard.guent...@gmail.com>> wrote: > > > > On Wed, Apr 26, 2023 at 12:56 PM <senthilkumar.selva...@microchip.com > > > > <mailto:senthilkumar.selva...@microchip.com>> wrote: > > > > > On Wed, Apr 26, 2023 at 3:15 PM Richard Biener via Gcc-patches > > > > > <gcc-patches@gcc.gnu.org <mailto:gcc-patches@gcc.gnu.org>> wrote: > > > > > > On Wed, Apr 26, 2023 at 11:42 AM Richard Biener > > > > > > <richard.guent...@gmail.com <mailto:richard.guent...@gmail.com>> > > > > > > wrote: > > > > > > > On Wed, Apr 26, 2023 at 11:01 AM SenthilKumar.Selvaraj--- via > > > > > > > Gcc-patches <gcc-patches@gcc.gnu.org > > > > > > > <mailto:gcc-patches@gcc.gnu.org>> wrote: > > > > > > > > Hi, > > > > > > > > > > > > > > > > This patch fixes PR 105523 by setting param_min_pagesize to 0 > > > > > > > > for the > > > > > > > > avr target. For this target, zero and offsets from zero are > > > > > > > > perfectly > > > > > > > > valid addresses, and the default value of param_min_pagesize > > > > > > > > ends up > > > > > > > > triggering warnings on valid memory accesses. > > > > > > > > > > > > > > I think the proper configuration is to have > > > > > > > DEFAULT_ADDR_SPACE_ZERO_ADDRESS_VALID > > > > > > > > > > > > Err, TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID > > > > > > > > > > That worked. Ok for trunk and backporting to 13 and 12 branches > > > > > (pending regression testing)? > > > > > > > > OK, but please let Denis time to comment. > > > > > > Didn't hear from Denis. When running regression tests with this patch, > > > I found that some tests with -fdelete-null-pointer-checks were > > > failing. Commit 19416210b37db0584cd0b3f3b3961324b8973d25 made > > > -fdelete-null-pointer-checks false by default, while still allowing it > > > to be overridden from the command line (it was previously > > > unconditionally false). > > > > > > To keep the same behavior, I modified the hook to report zero > > > addresses as valid only if -fdelete-null-pointer-checks is not set. > > > With this change, all regression tests pass. > > > > > > Ok for trunk and backporting to 13 and 12 branches? > > > > I think that's bit backwards - this hook conveys more precise information > > (it's address-space specific) and it is also more specific. Instead I'd > > suggest to set the flag to zero in the target like nios2 or msp430 do. > > In fact we should probably initialize it using this hook (and using the > > default address space). > > Does the below patch work? The hook impl reports that zero address is > valid, and flag_delete_null_pointer_checks is set to zero if the > hook says zero is a valid address. > > As flag_delete_null_pointer_checks is now always disabled for avr, I > removed the resetting code in avr-common.cc that disables it for > OPT_LEVELS_ALL by default, and added avr as a target that always keeps > null pointer checks in testsuite/lib/target-supports.exp. > > I also removed ATTRIBUTE_UNUSED and the parameter name in the target > hook to address > https://gcc.gnu.org/pipermail/gcc-patches/2023-May/619014.html. > > PR 105523 > > gcc/ChangeLog: > > * common/config/avr/avr-common.cc: Remove setting > of OPT_fdelete_null_pointer_checks. > * config/avr/avr.cc (avr_option_override): Clear > flag_delete_null_pointer_checks if zero_address_valid. > (avr_addr_space_zero_address_valid): New function. > (TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID): Provide target > hook. > > gcc/testsuite/ChangeLog: > > * lib/target-supports.exp > (check_effective_target_keeps_null_pointer_checks): Add > avr. > * gcc.target/avr/pr105523.c: New test. > > diff --git gcc/common/config/avr/avr-common.cc > gcc/common/config/avr/avr-common.cc > index 2ad0244..2f874c5 100644 > --- gcc/common/config/avr/avr-common.cc > +++ gcc/common/config/avr/avr-common.cc > @@ -29,12 +29,6 @@ > /* Implement TARGET_OPTION_OPTIMIZATION_TABLE. */ > static const struct default_options avr_option_optimization_table[] = > { > - // With -fdelete-null-pointer-checks option, the compiler assumes > - // that dereferencing of a null pointer would halt the program. > - // For AVR this assumption is not true and a program can safely > - // dereference null pointers. Changes made by this option may not > - // work properly for AVR. So disable this option. > - { OPT_LEVELS_ALL, OPT_fdelete_null_pointer_checks, NULL, 0 }, > // The only effect of -fcaller-saves might be that it triggers > // a frame without need when it tries to be smart around calls. > { OPT_LEVELS_ALL, OPT_fcaller_saves, NULL, 0 }, > diff --git gcc/config/avr/avr.cc gcc/config/avr/avr.cc > index a90cade..b987837 100644 > --- gcc/config/avr/avr.cc > +++ gcc/config/avr/avr.cc > @@ -756,6 +756,10 @@ avr_option_override (void) > flag_omit_frame_pointer = 0; > } > > + /* Disable flag_delete_null_pointer_checks if zero is a valid address. */ > + if (targetm.addr_space.zero_address_valid (ADDR_SPACE_GENERIC)) > + flag_delete_null_pointer_checks = 0; > + > if (flag_pic == 1) > warning (OPT_fpic, "%<-fpic%> is not supported"); > if (flag_pic == 2) > @@ -9800,6 +9804,16 @@ avr_addr_space_diagnose_usage (addr_space_t as, > location_t loc) > (void) avr_addr_space_supported_p (as, loc); > } > > +/* Implement `TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID. Zero is a valid > + address in all address spaces. Even in ADDR_SPACE_FLASH1 etc.., > + a zero address is valid and means 0x<RAMPZ val>0000, where RAMPZ is > + set to the appropriate segment value. */ > + > +static bool > +avr_addr_space_zero_address_valid (addr_space_t) > +{ > + return true; > +} > > /* Look if DECL shall be placed in program memory space by > means of attribute `progmem' or some address-space qualifier. > @@ -14760,6 +14774,9 @@ avr_float_lib_compare_returns_bool (machine_mode > mode, enum rtx_code) > #undef TARGET_ADDR_SPACE_DIAGNOSE_USAGE > #define TARGET_ADDR_SPACE_DIAGNOSE_USAGE avr_addr_space_diagnose_usage > > +#undef TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID > +#define TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID > avr_addr_space_zero_address_valid > + > #undef TARGET_MODE_DEPENDENT_ADDRESS_P > #define TARGET_MODE_DEPENDENT_ADDRESS_P avr_mode_dependent_address_p > > diff --git gcc/testsuite/gcc.target/avr/pr105523.c > gcc/testsuite/gcc.target/avr/pr105523.c > new file mode 100644 > index 0000000..fbbf7bf > --- /dev/null > +++ gcc/testsuite/gcc.target/avr/pr105523.c > @@ -0,0 +1,14 @@ > +/* { dg-do compile } */ > +/* { dg-options "-Os -Wall" } */ > + > +/* Verify no "array subscript 0 is outside array bounds of" is generated > + for accessing memory addresses in the 0-4096 range. */ > + > +typedef __UINT8_TYPE__ uint8_t; > + > +#define SREG (*(volatile uint8_t*) (0x3F + __AVR_SFR_OFFSET__ )) > + > +void bar (void) > +{ > + SREG = 0; > +} > diff --git gcc/testsuite/lib/target-supports.exp > gcc/testsuite/lib/target-supports.exp > index 263ef35..56fa73d 100644 > --- gcc/testsuite/lib/target-supports.exp > +++ gcc/testsuite/lib/target-supports.exp > @@ -686,7 +686,8 @@ proc check_effective_target_keeps_null_pointer_checks { } > { > if [target_info exists keeps_null_pointer_checks] { > return 1 > } > - if { [istarget msp430-*-*] } { > + if { [istarget msp430-*-*] > + || [istarget avr-*-*] } { > return 1; > } > return 0
[Ping] Re: [PATCH] avr: Set param_min_pagesize to 0 [PR105523]
SenthilKumar.Selvaraj--- via Gcc-patches Fri, 16 Jun 2023 03:18:20 -0700
- [Ping] Re: [PATCH] avr: Set param... SenthilKumar.Selvaraj--- via Gcc-patches
- Re: [Ping] Re: [PATCH] avr: ... Jeff Law via Gcc-patches
