Why doesn’t GCC optimize structs?

by

gcc does not reorder the elements of a struct, because that would violate the C standard. Section 6.7.2.1 of the C99 standard states:

Within a structure object, the non-bit-field members and the units in which bit-fields
reside have addresses that increase in the order in which they are declared.

More Related Contents:

  1. Competitive programming: "Time exceeded error"
  2. Disable all optimization options in GCC
  3. Is an empty initializer list valid C code?
  4. How to prevent GCC from optimizing out a busy wait loop?
  5. How many GCC optimization levels are there?
  6. Anonymous union within struct not in c99?
  7. Array of size 0 at the end of struct [duplicate]
  8. Does GCC’s __attribute__((__packed__)) retain the original ordering?
  9. Why does static initialization of flexible array member work?
  10. Produce loops without cmp instruction in GCC
  11. Query on -ffunction-section & -fdata-sections options of gcc
  12. Running C — helloWorld runs but nothing else — Ubuntu
  13. How to disable GCC warnings for a few lines of code
  14. Are compilers allowed to eliminate infinite loops?
  15. printf and long double
  16. Trying to understand gcc option -fomit-frame-pointer
  17. How can I use “sizeof” in a preprocessor macro?
  18. Why does the C preprocessor interpret the word “linux” as the constant “1”?
  19. How do I print uint32_t and uint16_t variables’ value?
  20. How to turn off gcc compiler optimization to enable buffer overflow
  21. Anonymous functions using GCC statement expressions
  22. Initializing a struct to 0
  23. why does GCC __builtin_prefetch not improve performance?
  24. Linking a C program directly with ld fails with undefined reference to `__libc_csu_fini`
  25. execute binary machine code from C
  26. How do you use offsetof() on a struct?
  27. How to tell GCC to generate 16-bit code for real mode
  28. Iterating over same type struct members in C
  29. GCC – no warning about an uninitialized array with -O0
  30. conflicting types error when compiling c program using gcc

Leave a Comment