]> git.ipfire.org Git - thirdparty/gcc.git/commitdiff
aarch64: Fold lsl+lsr+orr to rev for half-width shifts
authorDhruv Chawla <dhruvc@nvidia.com>
Wed, 18 Dec 2024 16:21:24 +0000 (08:21 -0800)
committerDhruv Chawla <dhruvc@nvidia.com>
Fri, 23 May 2025 08:04:10 +0000 (13:34 +0530)
This patch folds the following pattern:

  lsl <y>, <x>, <shift>
  lsr <z>, <x>, <shift>
  orr <r>, <y>, <z>

to:

  revb/h/w <r>, <x>

when the shift amount is equal to half the bitwidth of the <x>
register.

Bootstrapped and regtested on aarch64-linux-gnu.

Signed-off-by: Dhruv Chawla <dhruvc@nvidia.com>
Co-authored-by: Richard Sandiford <richard.sandiford@arm.com>
gcc/ChangeLog:

* expmed.cc (expand_rotate_as_vec_perm): Avoid a no-op move if the
target already provided the result in the expected register.
* config/aarch64/aarch64.cc (aarch64_vectorize_vec_perm_const):
Avoid forcing subregs into fresh registers unnecessarily.
* config/aarch64/aarch64-sve.md: Add define_split for rotate.
(*v_revvnx8hi): New pattern.

gcc/testsuite/ChangeLog:

* gcc.target/aarch64/sve/shift_rev_1.c: New test.
* gcc.target/aarch64/sve/shift_rev_2.c: Likewise.
* gcc.target/aarch64/sve/shift_rev_3.c: Likewise.

gcc/config/aarch64/aarch64-sve.md
gcc/config/aarch64/aarch64.cc
gcc/expmed.cc
gcc/testsuite/gcc.target/aarch64/sve/shift_rev_1.c [new file with mode: 0644]
gcc/testsuite/gcc.target/aarch64/sve/shift_rev_2.c [new file with mode: 0644]
gcc/testsuite/gcc.target/aarch64/sve/shift_rev_3.c [new file with mode: 0644]

index e1ec778b10df507f7eb93833baed7c5d39c32459..c5d3e8cd3b32bdaa4220680b96de345df5eb272f 100644 (file)
 ;; - REVW
 ;; -------------------------------------------------------------------------
 
+(define_split
+  [(set (match_operand:SVE_FULL_HSDI 0 "register_operand")
+       (rotate:SVE_FULL_HSDI
+         (match_operand:SVE_FULL_HSDI 1 "register_operand")
+         (match_operand:SVE_FULL_HSDI 2 "aarch64_constant_vector_operand")))]
+  "TARGET_SVE && can_create_pseudo_p ()"
+  [(set (match_dup 3)
+       (ashift:SVE_FULL_HSDI (match_dup 1)
+                             (match_dup 2)))
+   (set (match_dup 0)
+       (plus:SVE_FULL_HSDI
+         (lshiftrt:SVE_FULL_HSDI (match_dup 1)
+                                 (match_dup 4))
+         (match_dup 3)))]
+  {
+    if (aarch64_emit_opt_vec_rotate (operands[0], operands[1], operands[2]))
+      DONE;
+
+    if (!TARGET_SVE2)
+      FAIL;
+
+    operands[3] = gen_reg_rtx (<MODE>mode);
+    HOST_WIDE_INT shift_amount =
+      INTVAL (unwrap_const_vec_duplicate (operands[2]));
+    int bitwidth = GET_MODE_UNIT_BITSIZE (<MODE>mode);
+    operands[4] = aarch64_simd_gen_const_vector_dup (<MODE>mode,
+                                                    bitwidth - shift_amount);
+  }
+)
+
+;; The RTL combiners are able to combine "ior (ashift, ashiftrt)" to a "bswap".
+;; Match that as well.
+(define_insn_and_split "*v_revvnx8hi"
+  [(parallel
+    [(set (match_operand:VNx8HI 0 "register_operand" "=w")
+         (bswap:VNx8HI (match_operand 1 "register_operand" "w")))
+     (clobber (match_scratch:VNx8BI 2 "=Upl"))])]
+  "TARGET_SVE"
+  "#"
+  "&& 1"
+  [(set (match_dup 0)
+       (unspec:VNx8HI
+         [(match_dup 2)
+          (unspec:VNx8HI
+            [(match_dup 1)]
+            UNSPEC_REVB)]
+         UNSPEC_PRED_X))]
+  {
+    if (!can_create_pseudo_p ())
+      emit_move_insn (operands[2], CONSTM1_RTX (VNx8BImode));
+    else
+      operands[2] = aarch64_ptrue_reg (VNx8BImode);
+  }
+)
+
 ;; Predicated integer unary operations.
 (define_insn "@aarch64_pred_<optab><mode>"
   [(set (match_operand:SVE_FULL_I 0 "register_operand")
index 1fa3ec522c3a1da0579ce0bcbee3c27123f67b18..59ac08483f4de4da1e2522af0f1c7cc5279ecf41 100644 (file)
@@ -27091,11 +27091,17 @@ aarch64_vectorize_vec_perm_const (machine_mode vmode, machine_mode op_mode,
   d.op_mode = op_mode;
   d.op_vec_flags = aarch64_classify_vector_mode (d.op_mode);
   d.target = target;
-  d.op0 = op0 ? force_reg (op_mode, op0) : NULL_RTX;
+  d.op0 = op0;
+  if (d.op0 && !register_operand (d.op0, op_mode))
+    d.op0 = force_reg (op_mode, d.op0);
   if (op0 && d.one_vector_p)
     d.op1 = copy_rtx (d.op0);
   else
-    d.op1 = op1 ? force_reg (op_mode, op1) : NULL_RTX;
+    {
+      d.op1 = op1;
+      if (d.op1 && !register_operand (d.op1, op_mode))
+       d.op1 = force_reg (op_mode, d.op1);
+    }
   d.testing_p = !target;
 
   if (!d.testing_p)
index d5da199d033dd6cf762f82da72f97cc7cdc23e9e..be427dca5d9afeed2013954472dde3a5430169e0 100644 (file)
@@ -6324,7 +6324,8 @@ expand_rotate_as_vec_perm (machine_mode mode, rtx dst, rtx x, rtx amt)
                             qimode, perm_dst);
   if (!res)
     return NULL_RTX;
-  emit_move_insn (dst, lowpart_subreg (mode, res, qimode));
+  if (!rtx_equal_p (res, perm_dst))
+    emit_move_insn (dst, lowpart_subreg (mode, res, qimode));
   return dst;
 }
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_1.c b/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_1.c
new file mode 100644 (file)
index 0000000..29ed378
--- /dev/null
@@ -0,0 +1,83 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=armv8.2-a+sve" } */
+/* { dg-final { check-function-bodies "**" "" "" } } */
+
+#include <arm_sve.h>
+
+/*
+** ror32_sve_lsl_imm:
+**     ptrue   (p[0-3]).b, all
+**     revw    z0.d, \1/m, z0.d
+**     ret
+*/
+svuint64_t
+ror32_sve_lsl_imm (svuint64_t r)
+{
+  return svorr_u64_z (svptrue_b64 (), svlsl_n_u64_z (svptrue_b64 (), r, 32),
+                     svlsr_n_u64_z (svptrue_b64 (), r, 32));
+}
+
+/*
+** ror32_sve_lsl_operand:
+**     ptrue   (p[0-3]).b, all
+**     revw    z0.d, \1/m, z0.d
+**     ret
+*/
+svuint64_t
+ror32_sve_lsl_operand (svuint64_t r)
+{
+  svbool_t pt = svptrue_b64 ();
+  return svorr_u64_z (pt, svlsl_n_u64_z (pt, r, 32), svlsr_n_u64_z (pt, r, 32));
+}
+
+/*
+** ror16_sve_lsl_imm:
+**     ptrue   (p[0-3]).b, all
+**     revh    z0.s, \1/m, z0.s
+**     ret
+*/
+svuint32_t
+ror16_sve_lsl_imm (svuint32_t r)
+{
+  return svorr_u32_z (svptrue_b32 (), svlsl_n_u32_z (svptrue_b32 (), r, 16),
+                     svlsr_n_u32_z (svptrue_b32 (), r, 16));
+}
+
+/*
+** ror16_sve_lsl_operand:
+**     ptrue   (p[0-3]).b, all
+**     revh    z0.s, \1/m, z0.s
+**     ret
+*/
+svuint32_t
+ror16_sve_lsl_operand (svuint32_t r)
+{
+  svbool_t pt = svptrue_b32 ();
+  return svorr_u32_z (pt, svlsl_n_u32_z (pt, r, 16), svlsr_n_u32_z (pt, r, 16));
+}
+
+/*
+** ror8_sve_lsl_imm:
+**     ptrue   (p[0-3]).b, all
+**     revb    z0.h, \1/m, z0.h
+**     ret
+*/
+svuint16_t
+ror8_sve_lsl_imm (svuint16_t r)
+{
+  return svorr_u16_z (svptrue_b16 (), svlsl_n_u16_z (svptrue_b16 (), r, 8),
+                     svlsr_n_u16_z (svptrue_b16 (), r, 8));
+}
+
+/*
+** ror8_sve_lsl_operand:
+**     ptrue   (p[0-3]).b, all
+**     revb    z0.h, \1/m, z0.h
+**     ret
+*/
+svuint16_t
+ror8_sve_lsl_operand (svuint16_t r)
+{
+  svbool_t pt = svptrue_b16 ();
+  return svorr_u16_z (pt, svlsl_n_u16_z (pt, r, 8), svlsr_n_u16_z (pt, r, 8));
+}
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_2.c b/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_2.c
new file mode 100644 (file)
index 0000000..2d380b1
--- /dev/null
@@ -0,0 +1,63 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=armv8.2-a+sve" } */
+
+#include <arm_sve.h>
+
+#define PTRUE_B(BITWIDTH) svptrue_b##BITWIDTH ()
+
+#define ROR_SVE_LSL(NAME, INPUT_TYPE, SHIFT_AMOUNT, BITWIDTH)                  \
+  INPUT_TYPE                                                                   \
+  NAME##_imm (INPUT_TYPE r)                                                    \
+  {                                                                            \
+    return svorr_u##BITWIDTH##_z (PTRUE_B (BITWIDTH),                          \
+                                 svlsl_n_u##BITWIDTH##_z (PTRUE_B (BITWIDTH), \
+                                                          r, SHIFT_AMOUNT),   \
+                                 svlsr_n_u##BITWIDTH##_z (PTRUE_B (BITWIDTH), \
+                                                          r, SHIFT_AMOUNT));  \
+  }                                                                            \
+                                                                               \
+  INPUT_TYPE                                                                   \
+  NAME##_operand (INPUT_TYPE r)                                                \
+  {                                                                            \
+    svbool_t pt = PTRUE_B (BITWIDTH);                                          \
+    return svorr_u##BITWIDTH##_z (                                             \
+      pt, svlsl_n_u##BITWIDTH##_z (pt, r, SHIFT_AMOUNT),                       \
+      svlsr_n_u##BITWIDTH##_z (pt, r, SHIFT_AMOUNT));                          \
+  }
+
+/* Make sure that the pattern doesn't match incorrect bit-widths, eg. a shift of
+   8 matching the 32-bit mode.  */
+
+ROR_SVE_LSL (higher_ror32, svuint64_t, 64, 64);
+ROR_SVE_LSL (higher_ror16, svuint32_t, 32, 32);
+ROR_SVE_LSL (higher_ror8, svuint16_t, 16, 16);
+
+ROR_SVE_LSL (lower_ror32, svuint64_t, 16, 64);
+ROR_SVE_LSL (lower_ror16, svuint32_t, 8, 32);
+ROR_SVE_LSL (lower_ror8, svuint16_t, 4, 16);
+
+/* Check off-by-one cases.  */
+
+ROR_SVE_LSL (off_1_high_ror32, svuint64_t, 33, 64);
+ROR_SVE_LSL (off_1_high_ror16, svuint32_t, 17, 32);
+ROR_SVE_LSL (off_1_high_ror8, svuint16_t, 9, 16);
+
+ROR_SVE_LSL (off_1_low_ror32, svuint64_t, 31, 64);
+ROR_SVE_LSL (off_1_low_ror16, svuint32_t, 15, 32);
+ROR_SVE_LSL (off_1_low_ror8, svuint16_t, 7, 16);
+
+/* Check out of bounds cases.  */
+
+ROR_SVE_LSL (oob_ror32, svuint64_t, 65, 64);
+ROR_SVE_LSL (oob_ror16, svuint32_t, 33, 32);
+ROR_SVE_LSL (oob_ror8, svuint16_t, 17, 16);
+
+/* Check zero case.  */
+
+ROR_SVE_LSL (zero_ror32, svuint64_t, 0, 64);
+ROR_SVE_LSL (zero_ror16, svuint32_t, 0, 32);
+ROR_SVE_LSL (zero_ror8, svuint16_t, 0, 16);
+
+/* { dg-final { scan-assembler-times "\trevb\t" 0 } } */
+/* { dg-final { scan-assembler-times "\trevh\t" 0 } } */
+/* { dg-final { scan-assembler-times "\trevw\t" 0 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_3.c b/gcc/testsuite/gcc.target/aarch64/sve/shift_rev_3.c
new file mode 100644 (file)
index 0000000..126766d
--- /dev/null
@@ -0,0 +1,83 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=armv8.2-a+sve+sve2" } */
+/* { dg-final { check-function-bodies "**" "" "" } } */
+
+#include <arm_sve.h>
+
+/*
+** lsl_usra_32_sve_lsl_imm:
+**     lsl     z0.d, z1.d, #34
+**     usra    z0.d, z1.d, #30
+**     ret
+*/
+svuint64_t
+lsl_usra_32_sve_lsl_imm (svuint64_t __attribute__ ((unused)) dummy, svuint64_t r)
+{
+  return svorr_u64_z (svptrue_b64 (), svlsl_n_u64_z (svptrue_b64 (), r, 34),
+                     svlsr_n_u64_z (svptrue_b64 (), r, 30));
+}
+
+/*
+** lsl_usra_32_sve_lsl_operand:
+**     lsl     z0.d, z1.d, #34
+**     usra    z0.d, z1.d, #30
+**     ret
+*/
+svuint64_t
+lsl_usra_32_sve_lsl_operand (svuint64_t __attribute__ ((unused)) dummy, svuint64_t r)
+{
+  svbool_t pt = svptrue_b64 ();
+  return svorr_u64_z (pt, svlsl_n_u64_z (pt, r, 34), svlsr_n_u64_z (pt, r, 30));
+}
+
+/*
+** lsl_usra_16_sve_lsl_imm:
+**     lsl     z0.s, z1.s, #14
+**     usra    z0.s, z1.s, #18
+**     ret
+*/
+svuint32_t
+lsl_usra_16_sve_lsl_imm (svuint32_t __attribute__ ((unused)) dummy, svuint32_t r)
+{
+  return svorr_u32_z (svptrue_b32 (), svlsl_n_u32_z (svptrue_b32 (), r, 14),
+                     svlsr_n_u32_z (svptrue_b32 (), r, 18));
+}
+
+/*
+** lsl_usra_16_sve_lsl_operand:
+**     lsl     z0.s, z1.s, #14
+**     usra    z0.s, z1.s, #18
+**     ret
+*/
+svuint32_t
+lsl_usra_16_sve_lsl_operand (svuint32_t __attribute__ ((unused)) dummy, svuint32_t r)
+{
+  svbool_t pt = svptrue_b32 ();
+  return svorr_u32_z (pt, svlsl_n_u32_z (pt, r, 14), svlsr_n_u32_z (pt, r, 18));
+}
+
+/*
+** lsl_usra_8_sve_lsl_imm:
+**     lsl     z0.h, z1.h, #6
+**     usra    z0.h, z1.h, #10
+**     ret
+*/
+svuint16_t
+lsl_usra_8_sve_lsl_imm (svuint16_t __attribute__ ((unused)) dummy, svuint16_t r)
+{
+  return svorr_u16_z (svptrue_b16 (), svlsl_n_u16_z (svptrue_b16 (), r, 6),
+                     svlsr_n_u16_z (svptrue_b16 (), r, 10));
+}
+
+/*
+** lsl_usra_8_sve_lsl_operand:
+**     lsl     z0.h, z1.h, #6
+**     usra    z0.h, z1.h, #10
+**     ret
+*/
+svuint16_t
+lsl_usra_8_sve_lsl_operand (svuint16_t __attribute__ ((unused)) dummy, svuint16_t r)
+{
+  svbool_t pt = svptrue_b16 ();
+  return svorr_u16_z (pt, svlsl_n_u16_z (pt, r, 6), svlsr_n_u16_z (pt, r, 10));
+}