Hi Alan, On Mon, Jun 15, 2015 at 12:03:47PM +0930, Alan Modra wrote: > This patch changes the targetm.rtx_costs interface to pass a mode > parameter, and removes a redundant parameter. The reason for the > change is that powerpc and other backends need the mode that a > const_int is used in to properly determine the cost. For instance, > (set (reg) (ior (reg) (const_int))) where const_int is 0xff..ffff0000 > can be implemented in one instruction on powerpc if the regs and > constant are SImode, but not when DImode.
Nice :-) > Some backends work around this problem by calculating the cost of the > entire expression under the IOR, which allows the mode of the > const_int to be inferred. Yeah, I do this in my series to improve the PowerPC rotate-and-mask instructions. Some of the time you really have to look at a bigger part of the pattern, but your patch should help here. > sub-rtx's in rtx_cost are > summed in order rather than reverse order so that the mode from an > earlier operand can be used for a later operand lacking a mode. This > is for ZERO_EXTEND and similar codes where the sub-rtx mode is > different to the outer mode. Canonicalization puts const_int operands > after other operands. Not always; only for commutative operations, or operations that can be swapped (like comparisons). As a counterexample, see PowerPC subfic (imm - reg). > The testing showed some pre-existing bugs.. > > arc-elf dies on attempting to assemble first libgcc file, due to gas > not understanding the options being passed by gcc. Apparently no one > cared enough to push gas changes upstream. You need to configure it with --with-cpu. Not that that makes any sense :-) > ia64-linux, m68k-linux, tilegx-linux and tilepro-linux have > dependencies on include files, not solved by -Dinhibit_libc, so die > building libgcc. Can be solved by hand, but annoying. Very annoying yes. Have patches for all; will send. > s390x-linux doesn't build as a cross-compiler. undefined reference to > `s390_host_detect_local_cpu(int, char const**)' This is recent, maybe already fixed? Segher
