Displaying 1 result from an estimated 1 matches for "test_unused_regs".
2010 Jun 03
2
[LLVMdev] Unused argument registers can not be reused ?
...backend, with the 2.7 release as well as the svn head.
For the msp430, the first four parameters of a function are passed thru registers. What I observe is that if those parameters are not used inside the function, those registers can not be used.
For example, with the following C code:
> cat test_unused_regs.c
short a = 2;
short b = 32;
short r = 1024;
void
test(short w, short x, short y, short z)
{
r -= a+b;
}
I get the following assembly code for the test function after running thru clang:
> clang -ccc-host-triple msp430-unknown-unknown -O2 -fomit-frame-pointer -S -o test_unused_regs.s test_un...