[gcc r11-5127] MSP430: Add mul{hi,si} and {u,}mulsidi3 expanders

[Jozef Lawrynowicz]

https://gcc.gnu.org/g:e045b85836091f2461263a3c3f4f1972b3753f9d

commit r11-5127-ge045b85836091f2461263a3c3f4f1972b3753f9d
Author: Jozef Lawrynowicz <jozef.l@mittosystems.com>
Date:   Sun Nov 15 21:03:10 2020 +0000

    MSP430: Add mul{hi,si} and {u,}mulsidi3 expanders
    
    GCC generates better code when multiplication operations, which require
    library functions to perform, are caught in early in RTL, rather than
    leaving the operation to be mapped to a library function later on.
    
    When there is hardware multiply support, it is more efficient to perform
    widening multiplication using the hardware multiplier instead of letting
    GCC widen the arguments before calling the multiplication routine in the
    wider mode.
    
    gcc/ChangeLog:
    
            * config/msp430/msp430.md (mulhi3): New.
            (mulsi3): New.
            (mulsidi3): Rename to *mulsidi3_inline.
            (umulsidi3): Rename to *umulsidi3_inline.
            (mulsidi3): New define_expand.
            (umulsidi3): New define_expand.

Diff:
---
 gcc/config/msp430/msp430.md | 61 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 56 insertions(+), 5 deletions(-)

diff --git a/gcc/config/msp430/msp430.md b/gcc/config/msp430/msp430.md
index 65e951774b1..1ec219c0680 100644
--- a/gcc/config/msp430/msp430.md
+++ b/gcc/config/msp430/msp430.md
@@ -1724,6 +1724,28 @@
   [(set_attr "length" "2")]
 )
 
+(define_expand "mulhi3"
+  [(set (match_operand:HI			   0 "register_operand" "=r")
+	(mult:HI (match_operand:HI 1 "register_operand" "%0")
+		 (match_operand:HI 2 "register_operand" "r")))]
+  "msp430_has_hwmult ()"
+  {
+    msp430_expand_helper (operands, "__mspabi_mpyi", false);
+    DONE;
+  }
+)
+
+(define_expand "mulsi3"
+  [(set (match_operand:SI			   0 "register_operand" "=r")
+	(mult:SI (match_operand:SI 1 "register_operand" "%0")
+		 (match_operand:SI 2 "register_operand" "r")))]
+  "msp430_has_hwmult ()"
+  {
+    msp430_expand_helper (operands, "__mspabi_mpyl", false);
+    DONE;
+  }
+)
+
 ; 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.
@@ -1733,9 +1755,7 @@
 ; 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"))
@@ -1766,6 +1786,37 @@
   }
 )
 
+(define_expand "mulsidi3"
+  [(set (match_operand:DI			   0 "register_operand" "=r")
+	(mult:DI (sign_extend:DI (match_operand:SI 1 "register_operand" "%0"))
+		 (sign_extend:DI (match_operand:SI 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_mpysll", false);
+      DONE;
+    }
+  }
+)
+
+(define_expand "umulsidi3"
+  [(set (match_operand:DI			   0 "register_operand" "=r")
+	(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" "%0"))
+		 (zero_extend:DI (match_operand:SI 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_mpyull", 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"))
@@ -1794,7 +1845,7 @@
   [(set_attr "length" "24")]
 )
 
-(define_insn "mulsidi3"
+(define_insn "*mulsidi3_inline"
   [(set (match_operand:DI                          0 "register_operand" "=r")
 	(mult:DI (sign_extend:DI (match_operand:SI 1 "register_operand" "%0"))
 		 (sign_extend:DI (match_operand:SI 2 "register_operand" "r"))))]
@@ -1808,7 +1859,7 @@
   [(set_attr "length" "40")]
 )
 
-(define_insn "umulsidi3"
+(define_insn "*umulsidi3_inline"
   [(set (match_operand:DI                          0 "register_operand" "=r")
 	(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" "%0"))
 		 (zero_extend:DI (match_operand:SI 2 "register_operand" "r"))))]