• State Accepted Answer
  • Locked Locked
  • Replies 6 replies
  • Subscribers 22 subscribers
  • Views 3471 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Detection of warning depend on optimisation

fkl_at_deif

Hello arm

I use the arm v9-2019-q4-major toolchain. I compile for the STM32H743 (also seen in the setting)

I compile using the following settings. CFLAG contains compiler settings.

CFLAGS  += -D__FPU_PRESENT
CFLAGS  += -DARM_MATH_CM7
CFLAGS  += -DSTM32
CFLAGS  += -DSTM32H7
CFLAGS  += -DSTM32H743xx
CFLAGS  += -DSTM32H743XIHx
CFLAGS  += -std=c11
CFLAGS  += -mthumb
CFLAGS  += -mcpu=cortex-m7
CFLAGS  += -mfloat-abi=softfp
CFLAGS  += -mfpu=fpv5-d16
CFLAGS  += -g
CFLAGS  += -fmessage-length=0
CFLAGS  += -ffunction-sections
CFLAGS  += -fno-delete-null-pointer-checks

CFLAGS  += -Wstringop-overflow

CFLAGS  += -Werror
CFLAGS  += -Wall
CFLAGS  += -Wextra

CFLAGS  += -Wno-missing-field-initializers
CFLAGS  += -Wdouble-promotion

I wonder why I experience different warnings in my code depending on the optimisation?

I have tried with -O0, -O1, -O2, -O3 and -Os.

I find (relevant) warnings - eg warning of variables that might be used non initialised - with -O1, that is not found when compiling using higher levels?

I experience that the number of warnings found increases with the optimisation level. -O3 finds more warnings that -O1.

Best regards Frank.

0