[PATCH 2/5] rs6000: Fix TARGET_PROMOTE_FUNCTION_MODE

[Segher Boessenkool]

As the existing comment explains, we should always promote function
arguments and return values.  However, notwithstanding its name,
default_promote_function_mode_always_promote does not always promote.
Importantly, it does not for libcalls.  This makes ftrapv-[12].c fail
with 64-bit ABIs.

This patch introduces an rs6000_promote_function_mode that _does_
always promote, fixing this.

Tested as usual (c,c++,fortran,ada; -m32,-m32/-mpowerpc64,-m64,-m64/-mlra).
Is this okay for mainline?


Segher


2015-01-14  Segher Boessenkool  <segher@kernel.crashing.org>

gcc/
	* config/rs6000/rs6000.c (TARGET_PROMOTE_FUNCTION_MODE): Implement
	as rs6000_promote_function_mode.  Move comment to there.
	(rs6000_promote_function_mode): New function.

---
 gcc/config/rs6000/rs6000.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 4f8803d..ca5ce28 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1504,10 +1504,8 @@ static const struct attribute_spec rs6000_attribute_table[] =
 #undef TARGET_MEMBER_TYPE_FORCES_BLK
 #define TARGET_MEMBER_TYPE_FORCES_BLK rs6000_member_type_forces_blk
 
-/* On rs6000, function arguments are promoted, as are function return
-   values.  */
 #undef TARGET_PROMOTE_FUNCTION_MODE
-#define TARGET_PROMOTE_FUNCTION_MODE default_promote_function_mode_always_promote
+#define TARGET_PROMOTE_FUNCTION_MODE rs6000_promote_function_mode
 
 #undef TARGET_RETURN_IN_MEMORY
 #define TARGET_RETURN_IN_MEMORY rs6000_return_in_memory
@@ -9301,6 +9299,20 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, tree fntype,
     }
 }
 
+/* On rs6000, function arguments are promoted, as are function return
+   values.  */
+
+static machine_mode
+rs6000_promote_function_mode (const_tree type ATTRIBUTE_UNUSED,
+			      machine_mode mode,
+			      int *punsignedp ATTRIBUTE_UNUSED,
+			      const_tree, int)
+{
+  PROMOTE_MODE (mode, *punsignedp, type);
+
+  return mode;
+}
+
 /* Return true if TYPE must be passed on the stack and not in registers.  */
 
 static bool
-- 
1.8.1.4