[gcc r13-2440] RISC-V: Fix division instructions for `m` with `zmmul` extension.

[Kito Cheng]

https://gcc.gnu.org/g:ae97ba1efcd66d73d3631addf4c09f55e12d34f5

commit r13-2440-gae97ba1efcd66d73d3631addf4c09f55e12d34f5
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Mon Sep 5 21:36:45 2022 +0800

    RISC-V: Fix division instructions for `m` with `zmmul` extension.
    
    gcc/ChangeLog:
    
            * config/riscv/riscv.cc (riscv_option_override): Fix wrong
            condition for MASK_DIV and simplify incompatible checking.
            * config/riscv/riscv.md (muldi3): Adding parentheses.

Diff:
---
 gcc/config/riscv/riscv.cc | 8 ++------
 gcc/config/riscv/riscv.md | 2 +-
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index b5252b41df7..675d92c0961 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -5277,14 +5277,10 @@ riscv_option_override (void)
   /* The presence of the M extension implies that division instructions
      are present, so include them unless explicitly disabled.  */
   if (TARGET_MUL && (target_flags_explicit & MASK_DIV) == 0)
-    if(!TARGET_ZMMUL)
-      target_flags |= MASK_DIV;
+    target_flags |= MASK_DIV;
   else if (!TARGET_MUL && TARGET_DIV)
     error ("%<-mdiv%> requires %<-march%> to subsume the %<M%> extension");
-  
-  if(TARGET_ZMMUL && !TARGET_MUL && TARGET_DIV)
-    warning (0, "%<-mdiv%> cannot be used when %<ZMMUL%> extension is present");
-  
+
   /* Likewise floating-point division and square root.  */
   if (TARGET_HARD_FLOAT && (target_flags_explicit & MASK_FDIV) == 0)
     target_flags |= MASK_FDIV;
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index d2dfde28e31..014206fb8bd 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -752,7 +752,7 @@
   [(set (match_operand:DI          0 "register_operand" "=r")
 	(mult:DI (match_operand:DI 1 "register_operand" " r")
 		 (match_operand:DI 2 "register_operand" " r")))]
-  "TARGET_ZMMUL || TARGET_MUL && TARGET_64BIT"
+  "(TARGET_ZMMUL || TARGET_MUL) && TARGET_64BIT"
   "mul\t%0,%1,%2"
   [(set_attr "type" "imul")
    (set_attr "mode" "DI")])