arm: correctly handle misaligned MEMs on MVE [PR105463]

Vector operations in MVE must be aligned to the element size, so if we
are asked for a misaligned move in a wider mode we must recast it to a
form suitable for the known alignment (larger elements have better
address offset ranges, so there is some advantage to using wider
element sizes if possible).  Whilst fixing this, also rework the
predicates used for validating operands - the Neon predicates are
not right for MVE.

gcc/ChangeLog:

	PR target/105463
	* config/arm/mve.md (*movmisalign<mode>_mve_store): Use
	mve_memory_operand.
	(*movmisalign<mode>_mve_load): Likewise.
	* config/arm/vec-common.md (movmisalign<mode>): Convert to generator
	form...
	(@movmisalign<mode>): ... thus.  Use generic predicates and then
	rework operands if they are not valid.  For MVE rework to a
	narrower element size if the alignment is not high enough.

(cherry picked from commit 6a116728e27c4da65d84483c0e75561a7479d4d5)

diff --git a/gcc/config/arm/mve.md b/gcc/config/arm/mve.md
index 5c11885fb73f69bbcbe6565af02959202d900cfa..c9313744a16666000c9a36b8162a5813c024e526 100644 (file)
--- a/gcc/config/arm/mve.md
+++ b/gcc/config/arm/mve.md
@@ -10822,7 +10822,7 @@
 )
 
 (define_insn "*movmisalign<mode>_mve_store"
-  [(set (match_operand:MVE_VLD_ST 0 "neon_permissive_struct_operand"        "=Ux")
+  [(set (match_operand:MVE_VLD_ST 0 "mve_memory_operand"            "=Ux")
        (unspec:MVE_VLD_ST [(match_operand:MVE_VLD_ST 1 "s_register_operand" " w")]
         UNSPEC_MISALIGNED_ACCESS))]
   "((TARGET_HAVE_MVE && VALID_MVE_SI_MODE (<MODE>mode))
@@ -10835,7 +10835,7 @@
 
 (define_insn "*movmisalign<mode>_mve_load"
   [(set (match_operand:MVE_VLD_ST 0 "s_register_operand"                                "=w")
-       (unspec:MVE_VLD_ST [(match_operand:MVE_VLD_ST 1 "neon_permissive_struct_operand" " Ux")]
+       (unspec:MVE_VLD_ST [(match_operand:MVE_VLD_ST 1 "mve_memory_operand" " Ux")]
         UNSPEC_MISALIGNED_ACCESS))]
   "((TARGET_HAVE_MVE && VALID_MVE_SI_MODE (<MODE>mode))
     || (TARGET_HAVE_MVE_FLOAT && VALID_MVE_SF_MODE (<MODE>mode)))

diff --git a/gcc/config/arm/vec-common.md b/gcc/config/arm/vec-common.md
index 9212937380ff2abe9f7ff6d993da7049529dd5d5..581b05f845e27f02c512bcf8ed3878b862bfc0b0 100644 (file)
--- a/gcc/config/arm/vec-common.md
+++ b/gcc/config/arm/vec-common.md
@@ -280,29 +280,81 @@
   DONE;
 })
 
-(define_expand "movmisalign<mode>"
- [(set (match_operand:VDQX 0 "neon_perm_struct_or_reg_operand")
-       (unspec:VDQX [(match_operand:VDQX 1 "neon_perm_struct_or_reg_operand")]
+(define_expand "@movmisalign<mode>"
+ [(set (match_operand:VDQX 0 "nonimmediate_operand")
+       (unspec:VDQX [(match_operand:VDQX 1 "general_operand")]
         UNSPEC_MISALIGNED_ACCESS))]
  "ARM_HAVE_<MODE>_LDST && !BYTES_BIG_ENDIAN
   && unaligned_access && !TARGET_REALLY_IWMMXT"
 {
- rtx adjust_mem;
- /* This pattern is not permitted to fail during expansion: if both arguments
-    are non-registers (e.g. memory := constant, which can be created by the
-    auto-vectorizer), force operand 1 into a register.  */
- if (!s_register_operand (operands[0], <MODE>mode)
-     && !s_register_operand (operands[1], <MODE>mode))
-   operands[1] = force_reg (<MODE>mode, operands[1]);
-
- if (s_register_operand (operands[0], <MODE>mode))
-   adjust_mem = operands[1];
- else
-   adjust_mem = operands[0];
-
- /* Legitimize address.  */
- if (!neon_vector_mem_operand (adjust_mem, 2, true))
-   XEXP (adjust_mem, 0) = force_reg (Pmode, XEXP (adjust_mem, 0));
+  rtx *memloc;
+  bool for_store = false;
+  /* This pattern is not permitted to fail during expansion: if both arguments
+     are non-registers (e.g. memory := constant, which can be created by the
+     auto-vectorizer), force operand 1 into a register.  */
+  if (!s_register_operand (operands[0], <MODE>mode)
+      && !s_register_operand (operands[1], <MODE>mode))
+    operands[1] = force_reg (<MODE>mode, operands[1]);
+
+  if (s_register_operand (operands[0], <MODE>mode))
+    memloc = &operands[1];
+  else
+    {
+      memloc = &operands[0];
+      for_store = true;
+    }
+
+  /* For MVE, vector loads/stores must be aligned to the element size.  If the
+     alignment is less than that convert the load/store to a suitable mode.  */
+  if (TARGET_HAVE_MVE
+      && (MEM_ALIGN (*memloc)
+         < GET_MODE_ALIGNMENT (GET_MODE_INNER (<MODE>mode))))
+    {
+      scalar_mode new_smode;
+      switch (MEM_ALIGN (*memloc))
+       {
+       case 64:
+       case 32:
+         new_smode = SImode;
+         break;
+       case 16:
+         new_smode = HImode;
+         break;
+       default:
+         new_smode = QImode;
+         break;
+       }
+      machine_mode new_mode
+       = mode_for_vector (new_smode,
+                          GET_MODE_SIZE (<MODE>mode)
+                          / GET_MODE_SIZE (new_smode)).require ();
+      rtx new_mem = adjust_address (*memloc, new_mode, 0);
+
+      if (!for_store)
+       {
+         rtx reg = gen_reg_rtx (new_mode);
+         emit_insn (gen_movmisalign (new_mode, reg, new_mem));
+         emit_move_insn (operands[0], gen_lowpart (<MODE>mode, reg));
+         DONE;
+       }
+      emit_insn (gen_movmisalign (new_mode, new_mem,
+                                 gen_lowpart (new_mode, operands[1])));
+      DONE;
+    }
+
+  /* Legitimize address.  */
+  if ((TARGET_HAVE_MVE
+       && !mve_vector_mem_operand (<MODE>mode, XEXP (*memloc, 0), false))
+      || (!TARGET_HAVE_MVE
+         && !neon_vector_mem_operand (*memloc, 2, false)))
+    {
+      rtx new_mem
+       = replace_equiv_address (*memloc,
+                                force_reg (Pmode, XEXP (*memloc, 0)),
+                                false);
+      gcc_assert (MEM_ALIGN (new_mem) == MEM_ALIGN (*memloc));
+      *memloc = new_mem;
+    }
 })
 
 (define_insn "mve_vshlq_<supf><mode>"