RISC-V: Fix -msave-restore bug with sibcalls.

	2018-01-08  Monk Chiang  <sh.chiang04@gmail.com>
		    Kito Cheng  <kito.cheng@gmail.com>

	gcc/
	* config/riscv/riscv.c (machine_function::is_leaf): Remove field.
	(riscv_leaf_function_p): Delete.
	(riscv_function_ok_for_sibcall): Return false when TARGET_SAVE_RESTORE.

	2018-01-08  Chih-Mao Chen <pkmx.tw@gmail.com>
		    Monk Chiang  <sh.chiang04@gmail.com>

	gcc/testsuite/
	* gcc.target/riscv/save-restore-1.c: New.

From-SVN: r256362

gcc/ChangeLog

+2018-01-08  Monk Chiang  <sh.chiang04@gmail.com>
+	    Kito Cheng  <kito.cheng@gmail.com>
+
+	* config/riscv/riscv.c (machine_function::is_leaf): Remove field.
+	(riscv_leaf_function_p): Delete.
+	(riscv_function_ok_for_sibcall): Return false when TARGET_SAVE_RESTORE.
+
 2018-01-08  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	PR target/83677

gcc/config/riscv/riscv.c

@@ -127,9 +127,6 @@ struct GTY(())  machine_function {
      This area is allocated by the callee at the very top of the frame.  */
   int varargs_size;
 
-  /* Memoized return value of leaf_function_p.  <0 if false, >0 if true.  */
-  int is_leaf;
-
   /* The current frame information, calculated by riscv_compute_frame_info.  */
   struct riscv_frame_info frame;
 };
@@ -4176,26 +4173,15 @@ riscv_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
   emit_insn (gen_clear_cache (addr, end_addr));
 }
 
-/* Return leaf_function_p () and memoize the result.  */
-
-static bool
-riscv_leaf_function_p (void)
-{
-  if (cfun->machine->is_leaf == 0)
-    cfun->machine->is_leaf = leaf_function_p () ? 1 : -1;
-
-  return cfun->machine->is_leaf > 0;
-}
-
 /* Implement TARGET_FUNCTION_OK_FOR_SIBCALL.  */
 
 static bool
 riscv_function_ok_for_sibcall (tree decl ATTRIBUTE_UNUSED,
 			       tree exp ATTRIBUTE_UNUSED)
 {
-  /* When optimzing for size, don't use sibcalls in non-leaf routines */
+  /* Don't use sibcalls when use save-restore routine.  */
   if (TARGET_SAVE_RESTORE)
-    return riscv_leaf_function_p ();
+    return false;
 
   return true;
 }

gcc/testsuite/ChangeLog

+2018-01-08  Chih-Mao Chen <pkmx.tw@gmail.com>
+	    Monk Chiang  <sh.chiang04@gmail.com>
+
+	* gcc.target/riscv/save-restore-1.c: New.
+
 2018-01-08  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	PR target/83677

gcc/testsuite/gcc.target/riscv/save-restore-1.c

+/* { dg-do run } */
+/* { dg-options "-O2 -msave-restore -fomit-frame-pointer" } */
+
+#include <stdlib.h>
+
+__attribute__((noinline)) int g(void) { return 42; }
+
+__attribute__((noinline)) int f(void) {
+  asm volatile ("li s0, 0x87654321" ::: "s0");
+  return g();
+}
+
+int main(void) {
+  asm volatile ("li s0, 0x12345678" ::: "s0");
+
+  f();
+
+  long s0;
+  asm volatile ("mv %0, s0" : "=r"(s0));
+
+  if (s0 == 0x12345678)
+    exit (0);
+  else
+    abort();
+}