On 7/11/25 10:22 AM, Vladimir Makarov wrote: > On 7/8/25 9:43 PM, Xi Ruoyao wrote: >> >> IIUC "recog does not look at constraints until reload" has been a >> well-established rule in GCC for years and I don't have enough skill to >> challange it. So reallow reloading user hard registers (but still >> disallow doing so for asm) to fix the ICE.
I agree we should allow spilling of user defined hardregs outside of inline asms if needed. That said, I hesitate in spilling of hardregs (user defined or not) in any other scenarios. >> However before reload, recog completely ignores the constraints of >> insns, so the RTL passes may produce insns where some user hard >> registers violate an earlyclobber. Then we'll get an ICE without >> reloading them, like what we are recently encountering in LoongArch test >> suite. I wonder if the correct "fix" is to actually not generate the problematical rtl insn in the first place? Maybe recog() before lra should check for issues with early clobbers and constraints when there are hard registers involved? >> - /* Operands don't match. If the operands are >> - different user defined explicit hard >> + /* Operands don't match. For asm if the operands >> + are different user defined explicit hard >> registers, then we cannot make them match >> when one is early clobber operand. */ I know this existed before your patch, but: s/when one is early clobber operand/when one is an early clobber operand/ Peter
