On Tue, May 30, 2023 at 2:27 AM Takayuki 'January June' Suwa <jjsuwa_sys3...@yahoo.co.jp> wrote: > > The insn "*shlrd_reg" shifts two registers with a funnel shifter by the > third register to get a single word result: > > reg0 = (reg1 SHIFT_OP0 reg3) BIT_JOIN_OP (reg2 SHIFT_OP1 (32 - reg3)) > > where the funnel left shift is SHIFT_OP0 := ASHIFT, SHIFT_OP1 := LSHIFTRT > and its right shift is SHIFT_OP0 := LSHIFTRT, SHIFT_OP1 := ASHIFT, > respectively. And also, BIT_JOIN_OP can be either PLUS or IOR in either > shift direction. > > [(set (match_operand:SI 0 "register_operand" "=a") > (match_operator:SI 6 "xtensa_bit_join_operator" > [(match_operator:SI 4 "logical_shift_operator" > [(match_operand:SI 1 "register_operand" "r") > (match_operand:SI 3 "register_operand" "r")]) > (match_operator:SI 5 "logical_shift_operator" > [(match_operand:SI 2 "register_operand" "r") > (neg:SI (match_dup 3))])]))] > > Although the RTL matching template can express it as above, there is no > way of direcing that the operator (operands[6]) that combines the two > individual shifts is commutative. > Thus, if multiple insn sequences matching the above pattern appear > adjacently, the combiner may accidentally mix them up and get partial > results. > > This patch adds a new insn-and-split pattern with the two sides swapped > representation of the bit-combining operation that was lacking and > described above. > > And also changes the other "*shlrd" variants from previously describing > the arbitraryness of bit-combining operations with code iterators to a > combination of the match_operator and the predicate above. > > gcc/ChangeLog: > > * config/xtensa/predicates.md (xtensa_bit_join_operator): > New predicate. > * config/xtensa/xtensa.md (ior_op): Remove. > (*shlrd_reg): Rename from "*shlrd_reg_<code>", and add the > insn_and_split pattern of the same name to express and capture > the bit-combining operation with both sides swapped. > In addition, replace use of code iterator with new operator > predicate. > (*shlrd_const, *shlrd_per_byte): > Likewise regarding the code iterator. > --- > gcc/config/xtensa/predicates.md | 3 ++ > gcc/config/xtensa/xtensa.md | 81 ++++++++++++++++++++++----------- > 2 files changed, 58 insertions(+), 26 deletions(-)
Regtested for target=xtensa-linux-uclibc, no new regressions. I can also confirm that the pattern is now used as expected in the case where I previously had an issue. Thanks for fixing that! Committed to master. -- Thanks. -- Max
