This patch offers several insn-and-split patterns for bitwise AND with
register and constant that cannot fit into a "MOVI Ax, simm12" instruction,
but can be represented as:

i.   1's least significant N bits and the others 0's (17 <= N <= 31)
ii.  1's most significant N bits and the others 0's (12 <= N <= 31)
iii. M 1's sequence of bits and trailing N 0's bits
        (1 <= M <= 16, 1 <= N <= 30)

And also offers shortcuts for conditional branch if each of the abovementioned
operations is (not) equal to zero.

gcc/ChangeLog:

        * config/xtensa/predicates.md (shifted_mask_operand):
        New predicate.
        * config/xtensa/xtensa.md (*andsi3_const_pow2_minus_one):
        New insn-and-split pattern.
        (*andsi3_const_negative_pow2, *andsi3_const_shifted_mask,
        *masktrue_const_pow2_minus_one, *masktrue_const_negative_pow2,
        *masktrue_const_shifted_mask): Ditto.
---
 gcc/config/xtensa/predicates.md |  11 +++
 gcc/config/xtensa/xtensa.md     | 165 ++++++++++++++++++++++++++++++++
 2 files changed, 176 insertions(+)

diff --git a/gcc/config/xtensa/predicates.md b/gcc/config/xtensa/predicates.md
index bcc83ada0ae..24c77f343a0 100644
--- a/gcc/config/xtensa/predicates.md
+++ b/gcc/config/xtensa/predicates.md
@@ -52,6 +52,17 @@
            (match_test "xtensa_mask_immediate (INTVAL (op))"))
        (match_operand 0 "register_operand")))

+(define_predicate "shifted_mask_operand"
+  (and (match_code "const_int")
+       (match_test "!xtensa_simm12b (INTVAL (op))"))
+{
+  HOST_WIDE_INT mask = INTVAL (op);
+  int shift = ctz_hwi (mask);
+
+  return IN_RANGE (shift, 1, 31)
+        && xtensa_mask_immediate ((uint32_t)mask >> shift);
+})
+
 (define_predicate "extui_fldsz_operand"
   (and (match_code "const_int")
        (match_test "IN_RANGE (INTVAL (op), 1, 16)")))
diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 090a2939684..286a1d8c38e 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -645,6 +645,78 @@
    (set_attr "mode"  "SI")
    (set_attr "length"        "6")])

+(define_insn_and_split "*andsi3_const_pow2_minus_one"
+  [(set (match_operand:SI 0 "register_operand" "=a")
+       (and:SI (match_operand:SI 1 "register_operand" "r")
+               (match_operand:SI 2 "const_int_operand" "i")))]
+  "IN_RANGE (exact_log2 (INTVAL (operands[2]) + 1), 17, 31)"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+       (ashift:SI (match_dup 1)
+                  (match_dup 2)))
+   (set (match_dup 0)
+       (lshiftrt:SI (match_dup 0)
+                    (match_dup 2)))]
+{
+  operands[2] = GEN_INT (32 - floor_log2 (INTVAL (operands[2]) + 1));
+}
+  [(set_attr "type"  "arith")
+   (set_attr "mode"  "SI")
+   (set (attr "length")
+       (if_then_else (match_test "TARGET_DENSITY
+                                  && INTVAL (operands[2]) == 0x7FFFFFFF")
+                     (const_int 5)
+                     (const_int 6)))])
+
+(define_insn_and_split "*andsi3_const_negative_pow2"
+  [(set (match_operand:SI 0 "register_operand" "=a")
+       (and:SI (match_operand:SI 1 "register_operand" "r")
+               (match_operand:SI 2 "const_int_operand" "i")))]
+  "IN_RANGE (exact_log2 (-INTVAL (operands[2])), 12, 31)"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+       (lshiftrt:SI (match_dup 1)
+                    (match_dup 2)))
+   (set (match_dup 0)
+       (ashift:SI (match_dup 0)
+                  (match_dup 2)))]
+{
+  operands[2] = GEN_INT (floor_log2 (-INTVAL (operands[2])));
+}
+  [(set_attr "type"  "arith")
+   (set_attr "mode"  "SI")
+   (set_attr "length"        "6")])
+
+(define_insn_and_split "*andsi3_const_shifted_mask"
+  [(set (match_operand:SI 0 "register_operand" "=a")
+       (and:SI (match_operand:SI 1 "register_operand" "r")
+               (match_operand:SI 2 "shifted_mask_operand" "i")))]
+  ""
+  "#"
+  ""
+  [(set (match_dup 0)
+       (zero_extract:SI (match_dup 1)
+                        (match_dup 3)
+                        (match_dup 2)))
+   (set (match_dup 0)
+       (ashift:SI (match_dup 0)
+                  (match_dup 2)))]
+{
+  HOST_WIDE_INT mask = INTVAL (operands[2]);
+  int shift = ctz_hwi (mask);
+  operands[2] = GEN_INT (shift);
+  operands[3] = GEN_INT (floor_log2 (((uint32_t)mask >> shift) + 1));
+}
+  [(set_attr "type"  "arith")
+   (set_attr "mode"  "SI")
+   (set (attr "length")
+       (if_then_else (match_test "TARGET_DENSITY
+                                  && ctz_hwi (INTVAL (operands[2])) == 1")
+                     (const_int 5)
+                     (const_int 6)))])
+
 (define_insn "iorsi3"
   [(set (match_operand:SI 0 "register_operand" "=a")
        (ior:SI (match_operand:SI 1 "register_operand" "%r")
@@ -1648,6 +1720,99 @@
    (set_attr "mode"  "none")
    (set_attr "length"        "3")])

+(define_insn_and_split "*masktrue_const_pow2_minus_one"
+  [(set (pc)
+       (if_then_else (match_operator 4 "boolean_operator"
+                       [(zero_extract:SI (match_operand:SI 1 "register_operand" 
"r")
+                                         (match_operand:SI 2 "const_int_operand" 
"i")
+                                         (const_int 0))
+                        (const_int 0)])
+                     (label_ref (match_operand 3 "" ""))
+                     (pc)))
+   (clobber (match_scratch:SI 0 "=&a"))]
+  "IN_RANGE (INTVAL (operands[2]), 17, 31)"
+  "#"
+  "&& reload_completed"
+  [(set (match_dup 0)
+       (ashift:SI (match_dup 1)
+                  (match_dup 2)))
+   (set (pc)
+       (if_then_else (match_op_dup 4
+                       [(match_dup 0)
+                        (const_int 0)])
+                     (label_ref (match_dup 3))
+                     (pc)))]
+{
+  operands[2] = GEN_INT (32 - INTVAL (operands[2]));
+}
+  [(set_attr "type"  "jump")
+   (set_attr "mode"  "none")
+   (set (attr "length")
+       (if_then_else (match_test "TARGET_DENSITY
+                                  && INTVAL (operands[2]) == 31")
+                     (const_int 5)
+                     (const_int 6)))])
+
+(define_insn_and_split "*masktrue_const_negative_pow2"
+  [(set (pc)
+       (if_then_else (match_operator 4 "boolean_operator"
+                       [(and:SI (match_operand:SI 1 "register_operand" "r")
+                                (match_operand:SI 2 "const_int_operand" "i"))
+                        (const_int 0)])
+                     (label_ref (match_operand 3 "" ""))
+                     (pc)))
+   (clobber (match_scratch:SI 0 "=&a"))]
+  "IN_RANGE (exact_log2 (-INTVAL (operands[2])), 12, 30)"
+  "#"
+  "&& reload_completed"
+  [(set (match_dup 0)
+       (lshiftrt:SI (match_dup 1)
+                    (match_dup 2)))
+   (set (pc)
+       (if_then_else (match_op_dup 4
+                       [(match_dup 0)
+                        (const_int 0)])
+                     (label_ref (match_dup 3))
+                     (pc)))]
+{
+  operands[2] = GEN_INT (floor_log2 (-INTVAL (operands[2])));
+}
+  [(set_attr "type"  "jump")
+   (set_attr "mode"  "none")
+   (set_attr "length"        "6")])
+
+(define_insn_and_split "*masktrue_const_shifted_mask"
+  [(set (pc)
+       (if_then_else (match_operator 4 "boolean_operator"
+                       [(and:SI (match_operand:SI 1 "register_operand" "r")
+                                (match_operand:SI 2 "shifted_mask_operand" 
"i"))
+                        (const_int 0)])
+                     (label_ref (match_operand 3 "" ""))
+                     (pc)))
+   (clobber (match_scratch:SI 0 "=&a"))]
+  ""
+  "#"
+  "reload_completed"
+  [(set (match_dup 0)
+       (zero_extract:SI (match_dup 1)
+                        (match_dup 5)
+                        (match_dup 2)))
+   (set (pc)
+       (if_then_else (match_op_dup 4
+                       [(match_dup 0)
+                        (const_int 0)])
+                     (label_ref (match_dup 3))
+                     (pc)))]
+{
+  HOST_WIDE_INT mask = INTVAL (operands[2]);
+  int shift = ctz_hwi (mask);
+  operands[2] = GEN_INT (shift);
+  operands[5] = GEN_INT (floor_log2 (((uint32_t)mask >> shift) + 1));
+}
+  [(set_attr "type"  "jump")
+   (set_attr "mode"  "none")
+   (set_attr "length"        "6")])
+

 ;; Zero-overhead looping support.

--
2.20.1

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