[committed] RISC-V: Do not emit zcisr and zifencei if i-ext is 2.0

[Kito Cheng]

I-ext 2.0 already included zicsr and zifencei, skip that prevent
confusing binutils.

gcc/ChangeLog

        * common/config/riscv/riscv-common.cc (riscv_subset_list::to_string):
        Skip zicsr and zifencei if I-ext is 2.0.
---
 gcc/common/config/riscv/riscv-common.cc | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/gcc/common/config/riscv/riscv-common.cc 
b/gcc/common/config/riscv/riscv-common.cc
index 25f56707d94..a904893b9ed 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -488,6 +488,7 @@ riscv_subset_list::to_string (bool version_p) const
 
   bool skip_zifencei = false;
   bool skip_zicsr = false;
+  bool i2p0 = false;
 
   /* For RISC-V ISA version 2.2 or earlier version, zicsr and zifencei is
      included in the base ISA.  */
@@ -497,6 +498,13 @@ riscv_subset_list::to_string (bool version_p) const
       skip_zicsr = true;
     }
 
+  for (subset = m_head; subset != NULL; subset = subset->next)
+    if (subset->name == "i")
+      {
+       i2p0 = subset->major_version == 2 && subset->minor_version == 0;
+       break;
+      }
+
 #ifndef HAVE_AS_MISA_SPEC
   /* Skip since older binutils doesn't recognize zicsr.  */
   skip_zicsr = true;
@@ -509,10 +517,12 @@ riscv_subset_list::to_string (bool version_p) const
 
   for (subset = m_head; subset != NULL; subset = subset->next)
     {
-      if (subset->implied_p && skip_zifencei && subset->name == "zifencei")
+      if (((subset->implied_p && skip_zifencei) || i2p0) &&
+         subset->name == "zifencei")
        continue;
 
-      if (subset->implied_p && skip_zicsr && subset->name == "zicsr")
+      if (((subset->implied_p && skip_zicsr) || i2p0) &&
+         subset->name == "zicsr")
        continue;
 
       /* For !version_p, we only separate extension with underline for
-- 
2.34.0