msp430.c (msp430_expand_helper): Support expansion of calls to __mspabi_mpy* functions.

2019-10-30  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config/msp430/msp430.c (msp430_expand_helper): Support expansion of
	calls to __mspabi_mpy* functions.
	* config/msp430/msp430.md (mulhisi3): New define_expand.
	(umulhisi3): New define_expand.
	(*mulhisi3_inline): Use old mulhisi3 define_insn.
	(*umulhisi3_inline): Use old umulhisi3 define_insn.

From-SVN: r277624

3 files changed, 110 insertions, 14 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7b90915..70412cd 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,14 @@
 2019-10-30  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
 
+	* config/msp430/msp430.c (msp430_expand_helper): Support expansion of
+	calls to __mspabi_mpy* functions.
+	* config/msp430/msp430.md (mulhisi3): New define_expand.
+	(umulhisi3): New define_expand.
+	(*mulhisi3_inline): Use old mulhisi3 define_insn.
+	(*umulhisi3_inline): Use old umulhisi3 define_insn.
+
+2019-10-30  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
+
 	* config/msp430/msp430.c (msp430_check_index_not_high_mem): New.
 	(msp430_check_plus_not_high_mem): New.
 	(msp430_op_not_in_high_mem): Use new functions to check if the operand
diff --git a/gcc/config/msp430/msp430.c b/gcc/config/msp430/msp430.c
index a3d0d9c..c058690 100644
--- a/gcc/config/msp430/msp430.c
+++ b/gcc/config/msp430/msp430.c
@@ -53,6 +53,7 @@
 
 
 static void msp430_compute_frame_info (void);
+static bool use_32bit_hwmult (void);
 
 
 
@@ -2691,7 +2692,7 @@ void
 msp430_expand_helper (rtx *operands, const char *helper_name,
 		      bool const_variants)
 {
-  rtx c, f;
+  rtx c, fusage, fsym;
   char *helper_const = NULL;
   int arg1 = 12;
   int arg2 = 13;
@@ -2700,8 +2701,14 @@ msp430_expand_helper (rtx *operands, const char *helper_name,
   machine_mode arg1mode = GET_MODE (operands[1]);
   machine_mode arg2mode = GET_MODE (operands[2]);
   int have_430x = msp430x ? 1 : 0;
+  int expand_mpy = strncmp (helper_name, "__mspabi_mpy",
+			    sizeof ("__mspabi_mpy") - 1) == 0;
+  /* This function has been used incorrectly if CONST_VARIANTS is TRUE for a
+     hwmpy function.  */
+  gcc_assert (!(expand_mpy && const_variants));
 
-  if (CONST_INT_P (operands[2]))
+  /* Emit size-optimal insns for small shifts we can easily do inline.  */
+  if (CONST_INT_P (operands[2]) && !expand_mpy)
     {
       int i;
 
@@ -2718,6 +2725,10 @@ msp430_expand_helper (rtx *operands, const char *helper_name,
 	}
     }
 
+  if (arg1mode != VOIDmode && arg2mode != VOIDmode)
+    /* Modes of arguments must be equal if not constants.  */
+    gcc_assert (arg1mode == arg2mode);
+
   if (arg1mode == VOIDmode)
     arg1mode = arg0mode;
   if (arg2mode == VOIDmode)
@@ -2730,12 +2741,13 @@ msp430_expand_helper (rtx *operands, const char *helper_name,
     }
   else if (arg1mode == DImode)
     {
-      /* Shift value in R8:R11, shift amount in R12.  */
       arg1 = 8;
       arg1sz = 4;
       arg2 = 12;
     }
 
+  /* Use the "const_variant" of a shift library function if requested.
+     These are faster, but have larger code size.  */
   if (const_variants
       && CONST_INT_P (operands[2])
       && INTVAL (operands[2]) >= 1
@@ -2749,25 +2761,58 @@ msp430_expand_helper (rtx *operands, const char *helper_name,
 		(int) INTVAL (operands[2]));
     }
 
+  /* Setup the arguments to the helper function.  */
   emit_move_insn (gen_rtx_REG (arg1mode, arg1),
 		  operands[1]);
   if (!helper_const)
     emit_move_insn (gen_rtx_REG (arg2mode, arg2),
 		    operands[2]);
 
-  c = gen_call_value_internal (gen_rtx_REG (arg0mode, 12),
-			       gen_rtx_SYMBOL_REF (VOIDmode, helper_const
-						   ? helper_const
-						   : helper_name),
-			       GEN_INT (0));
+  if (expand_mpy)
+    {
+      if (msp430_use_f5_series_hwmult ())
+	fsym = gen_rtx_SYMBOL_REF (VOIDmode, concat (helper_name,
+						     "_f5hw", NULL));
+      else if (use_32bit_hwmult ())
+	{
+	  /* When the arguments are 16-bits, the 16-bit hardware multiplier is
+	     used.  */
+	  if (arg1mode == HImode)
+	    fsym = gen_rtx_SYMBOL_REF (VOIDmode, concat (helper_name,
+							 "_hw", NULL));
+	  else
+	    fsym = gen_rtx_SYMBOL_REF (VOIDmode, concat (helper_name,
+							 "_hw32", NULL));
+	}
+      /* 16-bit hardware multiply.  */
+      else if (msp430_has_hwmult ())
+	fsym = gen_rtx_SYMBOL_REF (VOIDmode, concat (helper_name,
+						     "_hw", NULL));
+      else
+	fsym = gen_rtx_SYMBOL_REF (VOIDmode, helper_name);
+    }
+  else
+    fsym = gen_rtx_SYMBOL_REF (VOIDmode,
+			       helper_const ? helper_const : helper_name);
+
+  c = gen_call_value_internal (gen_rtx_REG (arg0mode, 12), fsym, GEN_INT (0));
+
   c = emit_call_insn (c);
   RTL_CONST_CALL_P (c) = 1;
 
-  f = 0;
-  use_regs (&f, arg1, arg1sz);
+  /* Add register usage information for the arguments to the call.  */
+  fusage = NULL;
+  use_regs (&fusage, arg1, arg1sz);
   if (!helper_const)
-    use_regs (&f, arg2, 1);
-  add_function_usage_to (c, f);
+    {
+      /* If we are expanding a shift, we only need to use the low register
+	 for the shift amount.  */
+      if (!expand_mpy)
+	use_regs (&fusage, arg2, 1);
+      else
+	use_regs (&fusage, arg2, arg1sz);
+    }
+  add_function_usage_to (c, fusage);
 
   emit_move_insn (operands[0],
 		  /* Return value will always start in R12.  */
diff --git a/gcc/config/msp430/msp430.md b/gcc/config/msp430/msp430.md
index ed4c370..c3d8507 100644
--- a/gcc/config/msp430/msp430.md
+++ b/gcc/config/msp430/msp430.md
@@ -1642,7 +1642,49 @@
   "NOP"
   )
 
-(define_insn "mulhisi3"
+; libgcc helper functions for widening multiplication aren't currently
+; generated by gcc, so we can't catch them later and map them to the mspabi
+; functions.
+; We catch the patterns here and either generate a call to the helper function,
+; or emit the hardware multiply instruction sequence inline.
+;
+; If we don't have hardware multiply support, it will generally be slower and
+; result in larger code to call the mspabi library function to perform the
+; widening multiplication than just leaving GCC to widen the arguments itself.
+;
+; We don't use library functions for SImode->DImode widening since its always
+; larger and slower than letting GCC widen the arguments inline.
+(define_expand "mulhisi3"
+  [(set (match_operand:SI			   0 "register_operand" "=r")
+	(mult:SI (sign_extend:SI (match_operand:HI 1 "register_operand" "%0"))
+		 (sign_extend:SI (match_operand:HI 2 "register_operand" "r"))))]
+  "msp430_has_hwmult ()"
+  {
+    /* Leave the other case for the inline insn.  */
+    if (!(optimize > 2 && msp430_has_hwmult ()))
+    {
+      msp430_expand_helper (operands, "__mspabi_mpysl", false);
+      DONE;
+    }
+  }
+)
+
+(define_expand "umulhisi3"
+  [(set (match_operand:SI			   0 "register_operand" "=r")
+	(mult:SI (zero_extend:SI (match_operand:HI 1 "register_operand" "%0"))
+		 (zero_extend:SI (match_operand:HI 2 "register_operand" "r"))))]
+  "msp430_has_hwmult ()"
+  {
+    /* Leave the other case for the inline insn.  */
+    if (!(optimize > 2 && msp430_has_hwmult ()))
+    {
+      msp430_expand_helper (operands, "__mspabi_mpyul", false);
+      DONE;
+    }
+  }
+)
+
+(define_insn "*mulhisi3_inline"
   [(set (match_operand:SI                          0 "register_operand" "=r")
 	(mult:SI (sign_extend:SI (match_operand:HI 1 "register_operand" "%0"))
 		 (sign_extend:SI (match_operand:HI 2 "register_operand" "r"))))]
@@ -1655,7 +1697,7 @@
   "
 )
 
-(define_insn "umulhisi3"
+(define_insn "*umulhisi3_inline"
   [(set (match_operand:SI                          0 "register_operand" "=r")
 	(mult:SI (zero_extend:SI (match_operand:HI 1 "register_operand" "%0"))
 		 (zero_extend:SI (match_operand:HI 2 "register_operand" "r"))))]