RISC-V: c implies zca, and conditionally zcf & zcd

According to Zc-1.0.4-3.pdf from
https://github.com/riscvarchive/riscv-code-size-reduction/releases/tag/v1.0.4-3
The rule is that:
- C always implies Zca
- C+F implies Zcf (RV32 only)
- C+D implies Zcd

Signed-off-by: Fei Gao <gaofei@eswincomputing.com>
gcc/ChangeLog:

	* common/config/riscv/riscv-common.cc:
	c implies zca, and conditionally zcf & zcd.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/attribute-15.c: adapt TC.
	* gcc.target/riscv/attribute-16.c: likewise.
	* gcc.target/riscv/attribute-17.c: likewise.
	* gcc.target/riscv/attribute-18.c: likewise.
	* gcc.target/riscv/pr110696.c: likewise.
	* gcc.target/riscv/rvv/base/abi-callee-saved-1-zcmp.c: likewise.
	* gcc.target/riscv/rvv/base/abi-callee-saved-2-zcmp.c: likewise.
	* gcc.target/riscv/rvv/base/pr114352-1.c: likewise.
	* gcc.target/riscv/rvv/base/pr114352-3.c: likewise.
	* gcc.target/riscv/arch-39.c: New test.
	* gcc.target/riscv/arch-40.c: New test.

1 files changed, 12 insertions, 0 deletions

diff --git a/gcc/common/config/riscv/riscv-common.cc b/gcc/common/config/riscv/riscv-common.cc
index b0a16f5..3c4178c 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -82,6 +82,18 @@ static const riscv_implied_info_t riscv_implied_info[] =
   {"a", "zaamo"},
   {"a", "zalrsc"},
 
+  {"c", "zca"},
+  {"c", "zcf",
+   [] (const riscv_subset_list *subset_list) -> bool
+   {
+     return subset_list->xlen () == 32 && subset_list->lookup ("f");
+   }},
+  {"c", "zcd",
+   [] (const riscv_subset_list *subset_list) -> bool
+   {
+     return subset_list->lookup ("d");
+   }},
+
   {"zabha", "zaamo"},
 
   {"b", "zba"},