re PR target/63668 (-mstd-struct-return fails for non-leaf functions)

	PR target/63668
	* doc/invoke.texi (SPARC options): Document -mstd-struct-return.
	* config/sparc/sparc.c (sparc_struct_value_rtx): Minor tweaks.
	* config/sparc/sparc.h (CALL_REALLY_USED_REGISTERS): Define.
	* config/sparc/sparc.opt (mstd-struct-return): Accept negative form.

From-SVN: r231387

3 files changed, 33 insertions, 9 deletions

diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index ae96a9b..55ddacf 100644
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -7199,17 +7199,16 @@ sparc_struct_value_rtx (tree fndecl, int incoming)
 	  && TYPE_SIZE_UNIT (TREE_TYPE (fndecl))
 	  && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (fndecl))) == INTEGER_CST)
 	{
-	  /* We must check and adjust the return address, as it is
-	     optional as to whether the return object is really
-	     provided.  */
-	  rtx ret_reg = gen_rtx_REG (Pmode, 31);
+	  /* We must check and adjust the return address, as it is optional
+	     as to whether the return object is really provided.  */
+	  rtx ret_reg = gen_rtx_REG (Pmode, RETURN_ADDR_REGNUM);
 	  rtx scratch = gen_reg_rtx (SImode);
 	  rtx_code_label *endlab = gen_label_rtx ();
 
-	  /* Calculate the return object size */
+	  /* Calculate the return object size.  */
 	  tree size = TYPE_SIZE_UNIT (TREE_TYPE (fndecl));
 	  rtx size_rtx = GEN_INT (TREE_INT_CST_LOW (size) & 0xfff);
-	  /* Construct a temporary return value */
+	  /* Construct a temporary return value.  */
 	  rtx temp_val
 	    = assign_stack_local (Pmode, TREE_INT_CST_LOW (size), 0);
 
@@ -7221,13 +7220,13 @@ sparc_struct_value_rtx (tree fndecl, int incoming)
 	  emit_move_insn (scratch, gen_rtx_MEM (SImode,
 						plus_constant (Pmode,
 							       ret_reg, 8)));
-	  /* Assume the size is valid and pre-adjust */
+	  /* Assume the size is valid and pre-adjust.  */
 	  emit_insn (gen_add3_insn (ret_reg, ret_reg, GEN_INT (4)));
 	  emit_cmp_and_jump_insns (scratch, size_rtx, EQ, const0_rtx, SImode,
 				   0, endlab);
 	  emit_insn (gen_sub3_insn (ret_reg, ret_reg, GEN_INT (4)));
 	  /* Write the address of the memory pointed to by temp_val into
-	     the memory pointed to by mem */
+	     the memory pointed to by mem.  */
 	  emit_move_insn (mem, XEXP (temp_val, 0));
 	  emit_label (endlab);
 	}
diff --git a/gcc/config/sparc/sparc.h b/gcc/config/sparc/sparc.h
index d2782a4..d599418 100644
--- a/gcc/config/sparc/sparc.h
+++ b/gcc/config/sparc/sparc.h
@@ -696,6 +696,31 @@ extern enum cmodel sparc_cmodel;
 				\
   1, 1, 1, 1, 1, 1, 1}
 
+/* 1 for registers not available across function calls.
+   Unlike the above, this need not include the FIXED_REGISTERS, but any
+   registers that can be used without being saved.
+   The latter must include the registers where values are returned
+   and the register where structure-value addresses are passed.
+   Aside from that, you can include as many other registers as you like.  */
+
+#define CALL_REALLY_USED_REGISTERS  \
+ {1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  0, 0, 0, 0, 0, 0, 0, 0,	\
+  0, 0, 0, 0, 0, 0, 0, 0,	\
+				\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+				\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+  1, 1, 1, 1, 1, 1, 1, 1,	\
+				\
+  1, 1, 1, 1, 1, 1, 1}
+
 /* Return number of consecutive hard regs needed starting at reg REGNO
    to hold something of mode MODE.
    This is ordinarily the length in words of a value of mode MODE
diff --git a/gcc/config/sparc/sparc.opt b/gcc/config/sparc/sparc.opt
index 16583c3..a50ba05 100644
--- a/gcc/config/sparc/sparc.opt
+++ b/gcc/config/sparc/sparc.opt
@@ -203,7 +203,7 @@ Target RejectNegative Joined Var(sparc_debug_string)
 Enable debug output.
 
 mstd-struct-return
-Target Report RejectNegative Var(sparc_std_struct_return)
+Target Report Var(sparc_std_struct_return)
 Enable strict 32-bit psABI struct return checking.
 
 mfix-at697f