[gcc(refs/vendors/vrull/heads/for-upstream)] RISC-V: Use bseti/bclri/binvi to extend reach of ori/andi/xori

[gcc(refs/vendors/vrull/heads/for-upstream)] RISC-V: Use bseti/bclri/binvi to extend reach of ori/andi/xori

[Philipp Tomsich]

https://gcc.gnu.org/g:a4558d14cbdb2b32ef8a4282055d4090192dc7c1

commit a4558d14cbdb2b32ef8a4282055d4090192dc7c1
Author: Philipp Tomsich <philipp.tomsich@vrull.eu>
Date:   Tue Oct 11 23:42:48 2022 +0200

    RISC-V: Use bseti/bclri/binvi to extend reach of ori/andi/xori
    
    Sequences of the form "a | C" and "a ^ C" with C being the positive
    half of a signed immediate's range with one extra bit set in addition
    are mapped to ori/xori and one bseti/binvi to avoid using a temporary
    (and a multi-insn sequence to load C into that temporary).
    
    Something similar holds for "a & ~C" being representable as either
    bclri + bclri or bclri + andi.
    
    Commit-notes:
    - This no longer depends on "RISC-V: Optimize branches testing a
      bit-range or a shifted immediate".  The other series now needs to be
      adjusted before merging.
    END
    
    gcc/ChangeLog:
    
            * config/riscv/bitmanip.md (*<or_optab>i<mode>_extrabit):
            New pattern for binvi+binvi/xori and bseti+bseti/ori
            (*andi<mode>_extrabit): New pattern for bclri+bclri/andi
            * config/riscv/iterators.md (any_or): Match or and ior
            * config/riscv/predicates.md (const_twobits_operand):
            New predicate.
            (uimm_extra_bit_operand): New predicate.
            (uimm_extra_bit_or_twobits): New predicate.
            (not_uimm_extra_bit_operand): New predicate.
            (not_uimm_extra_bit_or_nottwobits): New predicate.
            * config/riscv/riscv.h (UIMM_EXTRA_BIT_OPERAND):
            Helper for the uimm_extra_bit_operand and
            not_uimm_extra_bit_operand predicates.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/riscv/zbs-bclri-02.c: New test.
            * gcc.target/riscv/zbs-binvi.c: New test.
            * gcc.target/riscv/zbs-bseti.c: New test.
    
    Series-to: gcc-patches@gcc.gnu.org
    Series-cc: Palmer Dabbelt <palmer@rivosinc.com>
    Series-cc: Vineet Gupta <vineetg@rivosinc.com>
    Series-cc: Christoph Muellner <christoph.muellner@vrull.eu>
    Series-cc: Kito Cheng <kito.cheng@gmail.com>
    Series-cc: Jeff Law <jlaw@ventanamicro.com>
    
    Series-version: 2
    Series-changes: 2
    - Collects already approved changes for v2 for (a | C) and (a ^ C).
    - Pulls in the (already) approved branch on polarity-reversed bits
      for v2, as it shares predicates with the other changes.
    - Newly adds support for the (a & ~C) case.
    
    Cover-letter:
    Use Zbs with xori/ori/andi and polarity-reversed twobit-tests
    
    We had a few patches on the list that shared predicates (for extending
    the reach of xori and ori -- and for the branches on two
    polarity-reversed bits) and thus depended on each other.
    
    These all had approval with requested changes, so these are now
    collected together for v2.
    
    Note that this adds the (a & ~C) case, so please take a look on that
    part and OK the updated series.
    
    Commit-changes: 2
    - Use an iterator for the ori/xori case and share one pattern
    - Adds the andi (a & ~C) case, expanding to bclri/andi.
    - Cleans up the predicates (incl. removing the non-intuitive inclusion
      of two-bits-set under the uimm_extra_bits)
    
    Series-notes:
    - This replaces the two earlier series that already had an OK and adds
      support for the "a & ~C" case... and merges the series for branches
      testing polarity-reversed bits for branches (to do away with the
      dependency).

Diff:
---
 gcc/config/riscv/bitmanip.md                       | 37 ++++++++++++++++++++++
 gcc/config/riscv/iterators.md                      |  8 +++++
 gcc/config/riscv/predicates.md                     | 36 +++++++++++++++------
 gcc/config/riscv/riscv.h                           |  8 +++++
 .../riscv/{zbs-bclri.c => zbs-bclri-01.c}          |  0
 gcc/testsuite/gcc.target/riscv/zbs-bclri-02.c      | 27 ++++++++++++++++
 gcc/testsuite/gcc.target/riscv/zbs-binvi.c         | 22 +++++++++++++
 gcc/testsuite/gcc.target/riscv/zbs-bseti.c         | 27 ++++++++++++++++
 8 files changed, 156 insertions(+), 9 deletions(-)

diff --git a/gcc/config/riscv/bitmanip.md b/gcc/config/riscv/bitmanip.md
index 481b579a462..c78a8bb70e3 100644
--- a/gcc/config/riscv/bitmanip.md
+++ b/gcc/config/riscv/bitmanip.md
@@ -662,3 +662,40 @@
   "TARGET_ZBS"
   [(set (match_dup 0) (zero_extract:GPR (match_dup 1) (const_int 1) (match_dup 2)))
    (set (match_dup 0) (plus:GPR (match_dup 0) (const_int -1)))])
+
+;; Catch those cases where we can use a bseti/binvi + ori/xori or
+;; bseti/binvi + bseti/binvi instead of a lui + addi + or/xor sequence.
+(define_insn_and_split "*<or_optab>i<mode>_extrabit"
+  [(set (match_operand:X 0 "register_operand" "=r")
+	(any_or:X (match_operand:X 1 "register_operand" "r")
+	          (match_operand:X 2 "uimm_extra_bit_or_twobits" "i")))]
+  "TARGET_ZBS"
+  "#"
+  "&& reload_completed"
+  [(set (match_dup 0) (<or_optab>:X (match_dup 1) (match_dup 3)))
+   (set (match_dup 0) (<or_optab>:X (match_dup 0) (match_dup 4)))]
+{
+	unsigned HOST_WIDE_INT bits = UINTVAL (operands[2]);
+	unsigned HOST_WIDE_INT topbit = HOST_WIDE_INT_1U << floor_log2 (bits);
+
+	operands[3] = GEN_INT (bits &~ topbit);
+	operands[4] = GEN_INT (topbit);
+})
+
+;; Same to use blcri + andi and blcri + bclri
+(define_insn_and_split "*andi<mode>_extrabit"
+  [(set (match_operand:X 0 "register_operand" "=r")
+	(and:X (match_operand:X 1 "register_operand" "r")
+	       (match_operand:X 2 "not_uimm_extra_bit_or_nottwobits" "i")))]
+  "TARGET_ZBS"
+  "#"
+  "&& reload_completed"
+  [(set (match_dup 0) (and:X (match_dup 1) (match_dup 3)))
+   (set (match_dup 0) (and:X (match_dup 0) (match_dup 4)))]
+{
+	unsigned HOST_WIDE_INT bits = UINTVAL (operands[2]);
+	unsigned HOST_WIDE_INT topbit = HOST_WIDE_INT_1U << floor_log2 (~bits);
+
+	operands[3] = GEN_INT (bits | topbit);
+	operands[4] = GEN_INT (~topbit);
+})
diff --git a/gcc/config/riscv/iterators.md b/gcc/config/riscv/iterators.md
index cbbf61f6514..efdd3ccc9a7 100644
--- a/gcc/config/riscv/iterators.md
+++ b/gcc/config/riscv/iterators.md
@@ -136,6 +136,10 @@
 ;; from the same template.
 (define_code_iterator any_bitwise [and ior xor])
 
+;; This code iterator allows ior and xor instructions to be generated
+;; from the same template.
+(define_code_iterator any_or [ior xor])
+
 ;; This code iterator allows unsigned and signed division to be generated
 ;; from the same template.
 (define_code_iterator any_div [div udiv mod umod])
@@ -194,6 +198,10 @@
 			 (plus "add")
 			 (minus "sub")])
 
+;; <or_optab> code attributes
+(define_code_attr or_optab [(ior "ior")
+			    (xor "xor")])
+
 ;; <insn> expands to the name of the insn that implements a particular code.
 (define_code_attr insn [(ashift "sll")
 			(ashiftrt "sra")
diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md
index 9058851df33..4b42c499ed1 100644
--- a/gcc/config/riscv/predicates.md
+++ b/gcc/config/riscv/predicates.md
@@ -309,15 +309,6 @@
        (match_test "ctz_hwi (INTVAL (op)) > 0")
        (match_test "SMALL_OPERAND (INTVAL (op) >> ctz_hwi (INTVAL (op)))")))
 
-;; A CONST_INT operand that fits into the unsigned half of a
-;; signed-immediate after the top bit has been cleared.
-(define_predicate "uimm_extra_bit_operand"
-  (and (match_code "const_int")
-       (not (and (match_test "SMALL_OPERAND (INTVAL (op))")
-		 (match_test "INTVAL (op) > 0")))
-       (ior (match_test "SMALL_OPERAND (UINTVAL (op) & ~(HOST_WIDE_INT_1U << floor_log2 (UINTVAL (op))))")
-	    (match_test "popcount_hwi (UINTVAL (op)) == 2"))))
-
 ;; A CONST_INT that can be shifted down by 1, 2 or 3 bits (i.e., has
 ;; these bits clear) and will then form a SMALL_OPERAND.
 (define_predicate "const_arith_shifted123_operand"
@@ -346,3 +337,30 @@
        (and (match_operand 0 "const_arith_shifted123_operand")
 	    (match_test "TARGET_ZBA"))))
 
+;; A CONST_INT operand that has exactly two bits set.
+(define_predicate "const_twobits_operand"
+  (and (match_code "const_int")
+       (match_test "popcount_hwi (UINTVAL (op)) == 2")))
+
+;; A CONST_INT operand that fits into the unsigned half of a
+;; signed-immediate after the top bit has been cleared
+(define_predicate "uimm_extra_bit_operand"
+  (and (match_code "const_int")
+       (match_test "UIMM_EXTRA_BIT_OPERAND (UINTVAL (op))")))
+
+(define_predicate "uimm_extra_bit_or_twobits"
+  (and (match_code "const_int")
+       (ior (match_operand 0 "uimm_extra_bit_operand")
+	    (match_operand 0 "const_twobits_operand"))))
+
+;; A CONST_INT operand that fits into the negative half of a
+;; signed-immediate after a single cleared top bit has been
+;; set: i.e., a bitwise-negated uimm_extra_bit_operand
+(define_predicate "not_uimm_extra_bit_operand"
+  (and (match_code "const_int")
+       (match_test "UIMM_EXTRA_BIT_OPERAND (~UINTVAL (op))")))
+
+(define_predicate "not_uimm_extra_bit_or_nottwobits"
+  (and (match_code "const_int")
+       (ior (match_operand 0 "not_uimm_extra_bit_operand")
+	    (match_operand 0 "const_nottwobits_operand"))))
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 2d0d170645c..b05c3c1545c 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -593,6 +593,14 @@ enum reg_class
 		? (VALUE)						\
 		: ((VALUE) & ((HOST_WIDE_INT_1U << 32)-1))))
 
+/* True if VALUE can be represented as an immediate with 1 extra bit
+   set: we check that it is not a SMALL_OPERAND (as this would be true
+   for all small operands) unmodified and turns into a small operand
+   once we clear the top bit. */
+#define UIMM_EXTRA_BIT_OPERAND(VALUE)					\
+  (!SMALL_OPERAND (VALUE)						\
+   && SMALL_OPERAND (VALUE & ~(HOST_WIDE_INT_1U << floor_log2 (VALUE))))
+
 /* Stack layout; function entry, exit and calling.  */
 
 #define STACK_GROWS_DOWNWARD 1
diff --git a/gcc/testsuite/gcc.target/riscv/zbs-bclri.c b/gcc/testsuite/gcc.target/riscv/zbs-bclri-01.c
similarity index 100%
rename from gcc/testsuite/gcc.target/riscv/zbs-bclri.c
rename to gcc/testsuite/gcc.target/riscv/zbs-bclri-01.c
diff --git a/gcc/testsuite/gcc.target/riscv/zbs-bclri-02.c b/gcc/testsuite/gcc.target/riscv/zbs-bclri-02.c
new file mode 100644
index 00000000000..61254844a4e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/zbs-bclri-02.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+long long f3(long long a)
+{
+  return a & ~0x1100;
+}
+
+long long f4 (long long a)
+{
+  return a & ~0x80000000000000ffull;
+}
+
+long long f5 (long long a)
+{
+  return a & ~0x8000001000000000ull;
+}
+
+long long f6 (long long a)
+{
+  return a & ~0xff7ffffffffffffull;
+}
+
+/* { dg-final { scan-assembler-times "bclri\t" 4 } } */
+/* { dg-final { scan-assembler-times "andi\t" 2 } } */
+
diff --git a/gcc/testsuite/gcc.target/riscv/zbs-binvi.c b/gcc/testsuite/gcc.target/riscv/zbs-binvi.c
new file mode 100644
index 00000000000..c2d6725b53b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/zbs-binvi.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+long long f3(long long a)
+{
+  return a ^ 0x1100;
+}
+
+long long f4 (long long a)
+{
+  return a ^ 0x80000000000000ffull;
+}
+
+long long f5 (long long a)
+{
+  return a ^ 0x8000001000000000ull;
+}
+
+/* { dg-final { scan-assembler-times "binvi\t" 4 } } */
+/* { dg-final { scan-assembler-times "xori\t" 2 } } */
+
diff --git a/gcc/testsuite/gcc.target/riscv/zbs-bseti.c b/gcc/testsuite/gcc.target/riscv/zbs-bseti.c
new file mode 100644
index 00000000000..5738add6348
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/zbs-bseti.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+long long foo1 (long long a)
+{
+  return a | 0x1100;
+}
+
+long long foo2 (long long a)
+{
+  return a | 0x80000000000000ffull;
+}
+
+long long foo3 (long long a)
+{
+  return a | 0x8000000100000000ull;
+}
+
+long long foo4 (long long a)
+{
+  return a | 0xfff;
+}
+
+/* { dg-final { scan-assembler-times "bseti\t" 5 } } */
+/* { dg-final { scan-assembler-times "ori\t" 3 } } */
+