[PATCH v3] RISC-V: Add Z*inx imcompatible check in gcc

[Jiawei <jiawei@iscas.ac.cn>]

Z*inx is conflict with float extensions, add incompatible check when
z*inx and f extension both enabled.

Since all float extension imply f extension and all z*inx extension 
imply zfinx extension, so we just need to check f with zfinx extension 
as the base case.

Co-Authored by: Kito Cheng <kito.cheng@gmail.com>

gcc/ChangeLog:

        * common/config/riscv/riscv-common.cc (riscv_subset_list::parse):
	* New check.

gcc/testsuite/ChangeLog:

        * gcc.target/riscv/arch-19.c: New test.

---
 gcc/common/config/riscv/riscv-common.cc  | 5 +++++
 gcc/testsuite/gcc.target/riscv/arch-19.c | 4 ++++
 2 files changed, 9 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/riscv/arch-19.c

diff --git a/gcc/common/config/riscv/riscv-common.cc b/gcc/common/config/riscv/riscv-common.cc
index ef221be1eb1..b3c6ec97e7a 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -1153,6 +1153,11 @@ riscv_subset_list::parse (const char *arch, location_t loc)
 
   subset_list->handle_combine_ext ();
 
+  if (subset_list->lookup("zfinx") && subset_list->lookup("f"))
+	error_at (loc,
+	"%<-march=%s%>: z*inx is conflict with float extensions",
+	arch);
+
   return subset_list;
 
 fail:
diff --git a/gcc/testsuite/gcc.target/riscv/arch-19.c b/gcc/testsuite/gcc.target/riscv/arch-19.c
new file mode 100644
index 00000000000..83c6e00a755
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/arch-19.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64if_zfinx -mabi=lp64" } */
+int foo() {}
+/* { dg-error "'-march=rv64if_zfinx': z\\*inx is conflict with float extensions" "" { target *-*-* } 0 } */
-- 
2.25.1