[gcc r11-8188] aarch64: Fix several *<LOGICAL:optab>_ashl<mode>3 related regressions [PR100056]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:39d23b7960e4efb11bbe1eff056ae9da0884c539

commit r11-8188-g39d23b7960e4efb11bbe1eff056ae9da0884c539
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Apr 15 10:45:09 2021 +0200

    aarch64: Fix several *<LOGICAL:optab>_ashl<mode>3 related regressions [PR100056]
    
    Before combiner added 2 to 2 combinations, the following testcase functions
    have been all compiled into 2 instructions, zero/sign extensions or and
    followed by orr with lsl, e.g. for the first function
    Trying 7 -> 8:
        7: r96:SI=r94:SI<<0xb
        8: r95:SI=r96:SI|r94:SI
          REG_DEAD r96:SI
          REG_DEAD r94:SI
    Successfully matched this instruction:
    (set (reg:SI 95)
        (ior:SI (ashift:SI (reg/v:SI 94 [ i ])
                (const_int 11 [0xb]))
            (reg/v:SI 94 [ i ])))
    is the important successful try_combine and so we end up with
            and     w0, w0, 255
            orr     w0, w0, w0, lsl 11
    in the body.
    With 2 to 2 combination, before that can trigger, another successful
    combination:
    Trying 2 -> 7:
        2: r94:SI=zero_extend(x0:QI)
          REG_DEAD x0:QI
        7: r96:SI=r94:SI<<0xb
    is replaced with:
    (set (reg/v:SI 94 [ i ])
        (zero_extend:SI (reg:QI 0 x0 [ i ])))
    and
    (set (reg:SI 96)
        (and:SI (ashift:SI (reg:SI 0 x0 [ i ])
                (const_int 11 [0xb]))
            (const_int 522240 [0x7f800])))
    and in the end results in 3 instructions in the body:
            and     w1, w0, 255
            ubfiz   w0, w0, 11, 8
            orr     w0, w0, w1
    The following combine splitters help undo that when combiner tries to
    combine 3 instructions - the zero/sign extend or and, the other insn
    from the 2 to 2 combination ([us]bfiz) and the logical op, the CPUs
    don't have an insn to do everything in one op, but we can split it
    back into the zero/sign extend or and followed by logical with lsl.
    
    2021-04-15  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/100056
            * config/aarch64/aarch64.md (*<LOGICAL:optab>_<SHIFT:optab><mode>3):
            Add combine splitters for *<LOGICAL:optab>_ashl<mode>3 with
            ZERO_EXTEND, SIGN_EXTEND or AND.
    
            * gcc.target/aarch64/pr100056.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64.md               | 53 ++++++++++++++++++++++++++
 gcc/testsuite/gcc.target/aarch64/pr100056.c | 58 +++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 9a7ed7866b1..962640b1f93 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -4431,6 +4431,59 @@
   [(set_attr "type" "logic_shift_imm")]
 )
 
+(define_split
+  [(set (match_operand:GPI 0 "register_operand")
+	(LOGICAL:GPI
+	  (and:GPI (ashift:GPI (match_operand:GPI 1 "register_operand")
+			       (match_operand:QI 2 "aarch64_shift_imm_<mode>"))
+		   (match_operand:GPI 3 "const_int_operand"))
+	  (zero_extend:GPI (match_operand 4 "register_operand"))))]
+  "can_create_pseudo_p ()
+   && ((paradoxical_subreg_p (operands[1])
+	&& rtx_equal_p (SUBREG_REG (operands[1]), operands[4]))
+       || (REG_P (operands[1])
+	   && REG_P (operands[4])
+	   && REGNO (operands[1]) == REGNO (operands[4])))
+   && (trunc_int_for_mode (GET_MODE_MASK (GET_MODE (operands[4]))
+			   << INTVAL (operands[2]), <MODE>mode)
+       == INTVAL (operands[3]))"
+  [(set (match_dup 5) (zero_extend:GPI (match_dup 4)))
+   (set (match_dup 0) (LOGICAL:GPI (ashift:GPI (match_dup 5) (match_dup 2))
+				   (match_dup 5)))]
+  "operands[5] = gen_reg_rtx (<MODE>mode);"
+)
+
+(define_split
+  [(set (match_operand:GPI 0 "register_operand")
+	(LOGICAL:GPI
+	  (and:GPI (ashift:GPI (match_operand:GPI 1 "register_operand")
+			       (match_operand:QI 2 "aarch64_shift_imm_<mode>"))
+		   (match_operand:GPI 4 "const_int_operand"))
+	  (and:GPI (match_dup 1) (match_operand:GPI 3 "const_int_operand"))))]
+  "can_create_pseudo_p ()
+   && pow2_or_zerop (UINTVAL (operands[3]) + 1)
+   && (trunc_int_for_mode (UINTVAL (operands[3])
+			   << INTVAL (operands[2]), <MODE>mode)
+       == INTVAL (operands[4]))"
+  [(set (match_dup 5) (and:GPI (match_dup 1) (match_dup 3)))
+   (set (match_dup 0) (LOGICAL:GPI (ashift:GPI (match_dup 5) (match_dup 2))
+				   (match_dup 5)))]
+  "operands[5] = gen_reg_rtx (<MODE>mode);"
+)
+
+(define_split
+  [(set (match_operand:GPI 0 "register_operand")
+	(LOGICAL:GPI
+	  (ashift:GPI (sign_extend:GPI (match_operand 1 "register_operand"))
+		      (match_operand:QI 2 "aarch64_shift_imm_<mode>"))
+	  (sign_extend:GPI (match_dup 1))))]
+  "can_create_pseudo_p ()"
+  [(set (match_dup 3) (sign_extend:GPI (match_dup 1)))
+   (set (match_dup 0) (LOGICAL:GPI (ashift:GPI (match_dup 3) (match_dup 2))
+				   (match_dup 3)))]
+  "operands[3] = gen_reg_rtx (<MODE>mode);"
+)
+
 (define_insn "*<optab>_rol<mode>3"
   [(set (match_operand:GPI 0 "register_operand" "=r")
 	(LOGICAL:GPI (rotate:GPI
diff --git a/gcc/testsuite/gcc.target/aarch64/pr100056.c b/gcc/testsuite/gcc.target/aarch64/pr100056.c
new file mode 100644
index 00000000000..0b77824da45
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr100056.c
@@ -0,0 +1,58 @@
+/* PR target/100056 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler-not {\t[us]bfiz\tw[0-9]+, w[0-9]+, 11} } } */
+
+int
+or_shift_u8 (unsigned char i)
+{
+  return i | (i << 11);
+}
+
+int
+or_shift_u3a (unsigned i)
+{
+  i &= 7;
+  return i | (i << 11);
+}
+
+int
+or_shift_u3b (unsigned i)
+{
+  i = (i << 29) >> 29;
+  return i | (i << 11);
+}
+
+int
+or_shift_s16 (signed short i)
+{
+  return i | (i << 11);
+}
+
+int
+or_shift_s8 (signed char i)
+{
+  return i | (i << 11);
+}
+
+int
+or_shift_s13 (int i)
+{
+  i = (i << 19) >> 19;
+  return i | (i << 11);
+}
+
+int
+or_shift_s3 (int i)
+{
+  i = (i << 29) >> 29;
+  return i | (i << 11);
+}
+
+int
+or_shift_u8_asm (unsigned char x)
+{
+  unsigned char i = x;
+  asm volatile ("" : "+r" (i));
+  return i | (i << 11);
+}