Issue mentioned: https://github.com/riscv/riscv-code-size-reduction/issues/182
The order of callee-saved registers stored by Zcmp push in memory is reversed.
Pseudo code for cm.push in https://github.com/riscv/riscv-code-size-reduction/releases/download/v1.0.4-1/Zc.1.0.4-1.pdf
if (XLEN==32) bytes=4; else bytes=8;
addr=sp-bytes;
for(i in 27,26,25,24,23,22,21,20,19,18,9,8,1) {
//if register i is in xreg_list
if (xreg_list[i]) {
switch(bytes) {
4: asm("sw x[i], 0(addr)");
8: asm("sd x[i], 0(addr)");
}
addr-=bytes;
}
}The placement order for push is s11, s10, ..., ra.
CFI offset should be calculed as reversed order for correct stack unwinding.
Nit:
I think this need more curly brackets around there:
if (FrameIdx < 0) { if (RVFI->isPushable(MF)) { ... } else { ... } } else { ... }