Ubuntu
gcc-11 package

  1. Bug #1953128
  2. Comment #17

Comment 17 for bug 1953128

Revision history for this message
In , Jakub-gcc (jakub-gcc) wrote :

CCing Frank as this is systemtap sys/sdt.h
which has:
# ifndef STAP_SDT_ARG_CONSTRAINT
# if defined __powerpc__
# define STAP_SDT_ARG_CONSTRAINT nZr
# else
# define STAP_SDT_ARG_CONSTRAINT nor
# endif
# endif

All of n, o and r are generic constraints and const0_rtx is valid for the "n" constraint, so why is the backend trying to put it into memory at all?
What is systemtap trying to do is not use those operands in any instruction, but note for the debugger how to find out the value of the asm input operand (read some register, some memory or the immediate constant).