> After reading the internal docs about rtx_costs I am left wondering what > they exactly are estimating. > - Are they estimating in the beginning of expand how many insns will be > generated from a particular insn until the assembler is generated? > - or Are they estimating how many assembler instructions will be > generated for a particular insn?
The latter is what they're *supposed* to be measuring, but of course it's an approximation.
