On Wed, Feb 24, 2016 at 10:34 AM, Kyrill Tkachov <kyrylo.tkac...@foss.arm.com> wrote: > Hi all, > > In this PR we get an ICE when the hoist pass ends up creating an > (insn 88 0 0 (set (reg:OI 136) > (const_int 0 [0])) -1 > (nil)) > > instruction. AArch64 doesn't support such an OImode set. > The only OImode set operations that aarch64 supports are load/store-multiple > operations > on vector registers. > > want_to_gcse_p should have rejected this move long before > process_insert_insn tried to > insert it in the stream. But it didn't because > can_assign_to_reg_without_clobbers_p is only > given the (const_int 0) expression and asked whether there can be a valid > SET operation on that. > It should also consider the mode that such an operation is requested in, > rather than extracting > the mode from the operand (VOIDmode for CONST_INTs). Luckily, want_to_gcse_p > already has a mode > argument that it uses in its costs calculation, so we can just pass it down. > > This patch extends can_assign_to_reg_without_clobbers_p to take a mode > argument and use it when > testing the validity of the SET instructions that it creates, so such an > OImode move is properly > rejected. > > Bootstrapped and tested on aarch64-none-linux-gnu, arm-none-linux-gnueabihf, > x86_64-unknown-linux-gnu. > There are no codegen differences on SPEC2006 for aarch64 resulting from this > patch. > > This bug appears in all versions that have aarch64, so it's not a > regression, but I think it's > a fairly low risk patch. > > Is this ok for trunk now or when stage 1 reopens?
Ok for trunk. Thanks, Richard. > Thanks, > Kyrill > > 2016-02-24 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > PR rtl-optimization/69886 > * gcse.c (can_assign_to_reg_without_clobbers_p): Accept mode > argument. Use it when checking validity of set instructions. > (want_to_gcse_p): Pass mode to can_assign_to_reg_without_clobbers_p. > (compute_ld_motion_mems): Update can_assign_to_reg_without_clobbers_p > callsite. > * rtl.h (can_assign_to_reg_without_clobbers_p): Update prototype. > * store-motion.c (find_moveable_store): Update > can_assign_to_reg_without_clobbers_p callsite. > > 2016-02-24 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > PR rtl-optimization/69886 > * gcc.dg/torture/pr69886.c: New test.
