The test-case gcc.target/cris/rld-legit1.c is a reduced test-case that required defining LEGITIMIZE_RELOAD_ADDRESS to stop the address from being decomposed into several insns by reload. Valid but suboptimal code was generated.
(Before implementing that hook for CRIS, the same test-case also exposed a bug in reload, and a fix was committed to avoid an ICE; see e.g. git r0-71992-gff0d9879ab0f30 and related commits. But, post-cc0, reload no longer handles this test-case without LEGITIMIZE_RELOAD_ADDRESS helping and there'd again an be ICE for CRIS (again: only if LEGITIMIZE_RELOAD_ADDRESS is disabled). There's a patch to reload to fix that, at https://gcc.gnu.org/pipermail/gcc-patches/2023-February/612039.html) But, LRA also does not handle that test-case gracefully, and like reload without LEGITIMIZE_RELOAD_ADDRESS for CRIS, decomposes the address into a suboptimal (but valid) sequence, about as messy as that from reload, and gcc.target/cris/rld-legit1.c would regress for LRA. There's nothing equivalent to LEGITIMIZE_RELOAD_ADDRESS for LRA. (Stepping through LRA, I can't find an obvious place where to put such a hook. Granted, I haven't seen this kind of messy decomposition in other code, so I'm not insisting a LEGITIMIZE_RELOAD_ADDRESS-like hook is a good idea.) These new peephole2's are required to not regress gcc.target/cris/rld-legit1.c with LRA enabled for CRIS. They don't appear to otherwise make a difference for neither libgcc, newlib libc, my own at-a-glance tests nor coremark, for neither LRA nor reload. * config/cris/cris.md (BW2): New mode-iterator. (lra_szext_decomposed, lra_szext_decomposed_indirect_with_offset): New peephole2s. --- gcc/config/cris/cris.md | 50 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/gcc/config/cris/cris.md b/gcc/config/cris/cris.md index 2bea480a0200..c3de259983c6 100644 --- a/gcc/config/cris/cris.md +++ b/gcc/config/cris/cris.md @@ -183,6 +183,10 @@ (define_mode_iterator SI_ [SI]) (define_mode_iterator WD [SI HI]) (define_mode_iterator BW [HI QI]) + +; Another "BW" for use where an independent iteration is needed. +(define_mode_iterator BW2 [HI QI]) + (define_mode_attr S [(SI "HI") (HI "QI")]) (define_mode_attr s [(SI "hi") (HI "qi")]) (define_mode_attr m [(SI ".d") (HI ".w") (QI ".b")]) @@ -2832,6 +2836,52 @@ (define_peephole2 ; andqu operands[3] = gen_rtx_ZERO_EXTEND (SImode, op1); operands[4] = GEN_INT (trunc_int_for_mode (INTVAL (operands[1]), QImode)); }) + +;; Fix a decomposed szext: fuse it with the memory operand of the +;; load. This is typically the sign-extension part of a decomposed +;; "indirect offset" address. +(define_peephole2 ; lra_szext_decomposed + [(parallel + [(set (match_operand:BW 0 "register_operand") + (match_operand:BW 1 "memory_operand")) + (clobber (reg:CC CRIS_CC0_REGNUM))]) + (parallel + [(set (match_operand:SI 2 "register_operand") (szext:SI (match_dup 0))) + (clobber (reg:CC CRIS_CC0_REGNUM))])] + "REGNO (operands[0]) == REGNO (operands[2]) + || peep2_reg_dead_p (2, operands[0])" + [(parallel + [(set (match_dup 2) (szext:SI (match_dup 1))) + (clobber (reg:CC CRIS_CC0_REGNUM))])]) + +;; Re-compose a decomposed "indirect offset" address for a szext +;; operation. The non-clobbering "addi" is generated by LRA. +;; This and lra_szext_decomposed is covered by cris/rld-legit1.c. +(define_peephole2 ; lra_szext_decomposed_indirect_with_offset + [(parallel + [(set (match_operand:SI 0 "register_operand") + (sign_extend:SI (mem:BW (match_operand:SI 1 "register_operand")))) + (clobber (reg:CC CRIS_CC0_REGNUM))]) + (set (match_dup 0) + (plus:SI (match_dup 0) (match_operand:SI 2 "register_operand"))) + (parallel + [(set (match_operand:SI 3 "register_operand") + (szext:SI (mem:BW2 (match_dup 0)))) + (clobber (reg:CC CRIS_CC0_REGNUM))])] + "(REGNO (operands[0]) == REGNO (operands[3]) + || peep2_reg_dead_p (3, operands[0])) + && (REGNO (operands[0]) == REGNO (operands[1]) + || peep2_reg_dead_p (3, operands[0]))" + [(parallel + [(set + (match_dup 3) + (szext:SI + (mem:BW2 (plus:SI (szext:SI (mem:BW (match_dup 1))) (match_dup 2))))) + (clobber (reg:CC CRIS_CC0_REGNUM))])]) + +;; Add operations with similar or same decomposed addresses here, when +;; encountered - but only when covered by mentioned test-cases for at +;; least one of the cases generalized in the pattern. ;; Local variables: ;; mode:emacs-lisp -- 2.30.2