RISC-V: Enable compressible features when use ZC* extensions.

This patch enables the compressible features with ZC* extensions.

Since all ZC* extension depends on the Zca extension, it's sufficient to only
add the target Zca to extend the target RVC.

Co-Authored by: Mary Bennett <mary.bennett@embecosm.com>
Co-Authored by: Nandni Jamnadas <nandni.jamnadas@embecosm.com>
Co-Authored by: Simon Cook <simon.cook@embecosm.com>

gcc/ChangeLog:

	* config/riscv/riscv-c.cc (riscv_cpu_cpp_builtins):
	Enable compressed builtins when ZC* extensions enabled.
	* config/riscv/riscv-shorten-memrefs.cc:
	Enable shorten_memrefs pass when ZC* extensions enabled.
	* config/riscv/riscv.cc (riscv_compressed_reg_p):
	Enable compressible registers when ZC* extensions enabled.
	(riscv_rtx_costs): Allow adjusting rtx costs when ZC* extensions enabled.
	(riscv_address_cost): Allow adjusting address cost when ZC* extensions enabled.
	(riscv_first_stack_step): Allow compression of the register saves
	without adding extra instructions.
	* config/riscv/riscv.h (FUNCTION_BOUNDARY): Adjusts function boundary
	to 16 bits when ZC* extensions enabled.

4 files changed, 11 insertions, 7 deletions

diff --git a/gcc/config/riscv/riscv-c.cc b/gcc/config/riscv/riscv-c.cc
index 6ad562d..2937c16 100644
--- a/gcc/config/riscv/riscv-c.cc
+++ b/gcc/config/riscv/riscv-c.cc
@@ -47,7 +47,7 @@ riscv_cpu_cpp_builtins (cpp_reader *pfile)
 {
   builtin_define ("__riscv");
 
-  if (TARGET_RVC)
+  if (TARGET_RVC || TARGET_ZCA)
     builtin_define ("__riscv_compressed");
 
   if (TARGET_RVE)
diff --git a/gcc/config/riscv/riscv-shorten-memrefs.cc b/gcc/config/riscv/riscv-shorten-memrefs.cc
index 8f10d24..6f2b973 100644
--- a/gcc/config/riscv/riscv-shorten-memrefs.cc
+++ b/gcc/config/riscv/riscv-shorten-memrefs.cc
@@ -65,7 +65,8 @@ public:
   /* opt_pass methods: */
   virtual bool gate (function *)
     {
-      return TARGET_RVC && riscv_mshorten_memrefs && optimize > 0;
+      return (TARGET_RVC || TARGET_ZCA)
+	&& riscv_mshorten_memrefs && optimize > 0;
     }
   virtual unsigned int execute (function *);
 
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index f9b7a9e..49062be 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -1227,7 +1227,8 @@ static bool
 riscv_compressed_reg_p (int regno)
 {
   /* x8-x15/f8-f15 are compressible registers.  */
-  return (TARGET_RVC && (IN_RANGE (regno, GP_REG_FIRST + 8, GP_REG_FIRST + 15)
+  return ((TARGET_RVC  || TARGET_ZCA)
+	  && (IN_RANGE (regno, GP_REG_FIRST + 8, GP_REG_FIRST + 15)
 	  || IN_RANGE (regno, FP_REG_FIRST + 8, FP_REG_FIRST + 15)));
 }
 
@@ -2530,7 +2531,8 @@ riscv_rtx_costs (rtx x, machine_mode mode, int outer_code, int opno ATTRIBUTE_UN
 	  /* When optimizing for size, make uncompressible 32-bit addresses
 	     more expensive so that compressible 32-bit addresses are
 	     preferred.  */
-	  if (TARGET_RVC && !speed && riscv_mshorten_memrefs && mode == SImode
+	  if ((TARGET_RVC || TARGET_ZCA)
+	      && !speed && riscv_mshorten_memrefs && mode == SImode
 	      && !riscv_compressed_lw_address_p (XEXP (x, 0)))
 	    cost++;
 
@@ -2956,7 +2958,8 @@ riscv_address_cost (rtx addr, machine_mode mode,
 {
   /* When optimizing for size, make uncompressible 32-bit addresses more
    * expensive so that compressible 32-bit addresses are preferred.  */
-  if (TARGET_RVC && !speed && riscv_mshorten_memrefs && mode == SImode
+  if ((TARGET_RVC || TARGET_ZCA)
+      && !speed && riscv_mshorten_memrefs && mode == SImode
       && !riscv_compressed_lw_address_p (addr))
     return riscv_address_insns (addr, mode, false) + 1;
   return riscv_address_insns (addr, mode, false);
@@ -5839,7 +5842,7 @@ riscv_first_stack_step (struct riscv_frame_info *frame, poly_int64 remaining_siz
       && remaining_const_size % IMM_REACH >= min_first_step)
     return remaining_const_size % IMM_REACH;
 
-  if (TARGET_RVC)
+  if (TARGET_RVC || TARGET_ZCA)
     {
       /* If we need two subtracts, and one is small enough to allow compressed
 	 loads and stores, then put that one first.  */
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 746101e..e18a008 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -186,7 +186,7 @@ ASM_MISA_SPEC
 #define PARM_BOUNDARY BITS_PER_WORD
 
 /* Allocation boundary (in *bits*) for the code of a function.  */
-#define FUNCTION_BOUNDARY (TARGET_RVC ? 16 : 32)
+#define FUNCTION_BOUNDARY ((TARGET_RVC || TARGET_ZCA) ? 16 : 32)
 
 /* The smallest supported stack boundary the calling convention supports.  */
 #define STACK_BOUNDARY \