[RFC 1/5] gcc: xtensa: allow XCHAL_* macros to be non-constant

[Max Filippov]

XCHAL_* macros from the xtensa-config.h are used in a number of places
that require them to be preprocessor constants. Rewrite these places so
that non-constant XCHAL_* definitions could be used there.

2017-05-22  Max Filippov  <jcmvb...@gmail.com>
gcc/
        * config/xtensa/xtensa.c (xtensa_option_override): Append
        MASK_CONST16 to target_flags in the absence of TARGET_L32R.
        (hwloop_optimize, hwloop_fail, hwloop_pattern_reg,
         xtensa_doloop_hooks): Define unconditionally.
        (xtensa_reorg_loops): Only call reorg_loops in the presence of
        TARGET_LOOPS.
        * config/xtensa/xtensa.h (TARGET_L32R): New definition.
        (TARGET_DEFAULT): Remove XCHAL_HAVE_L32R condition and account
        for it in xtensa_option_override.
        (HARD_FRAME_POINTER_IS_FRAME_POINTER,
         HARD_FRAME_POINTER_IS_ARG_POINTER): New definitions.
---
 gcc/config/xtensa/xtensa.c | 18 +++++++++---------
 gcc/config/xtensa/xtensa.h | 11 ++++++++---
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/gcc/config/xtensa/xtensa.c b/gcc/config/xtensa/xtensa.c
index 0181dde..8b20c64 100644
--- a/gcc/config/xtensa/xtensa.c
+++ b/gcc/config/xtensa/xtensa.c
@@ -2181,6 +2181,13 @@ xtensa_option_override (void)
   int regno;
   machine_mode mode;
 
+  /* Use CONST16 in the absence of L32R.
+     Set it in the TARGET_OPTION_OVERRIDE to avoid dependency on xtensa
+     configuration in the xtensa-common.c  */
+
+  if (!TARGET_L32R)
+    target_flags |= MASK_CONST16;
+
   if (!TARGET_BOOLEANS && TARGET_HARD_FLOAT)
     error ("boolean registers required for the floating-point option");
 
@@ -4053,8 +4060,6 @@ xtensa_invalid_within_doloop (const rtx_insn *insn)
 
 /* Optimize LOOP.  */
 
-#if TARGET_LOOPS
-
 static bool
 hwloop_optimize (hwloop_info loop)
 {
@@ -4241,14 +4246,9 @@ static struct hw_doloop_hooks xtensa_doloop_hooks =
 static void
 xtensa_reorg_loops (void)
 {
-  reorg_loops (false, &xtensa_doloop_hooks);
-}
-#else
-static inline void
-xtensa_reorg_loops (void)
-{
+  if (TARGET_LOOPS)
+    reorg_loops (false, &xtensa_doloop_hooks);
 }
-#endif
 
 /* Implement the TARGET_MACHINE_DEPENDENT_REORG pass.  */
 
diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
index c32e8ca..59d6b00 100644
--- a/gcc/config/xtensa/xtensa.h
+++ b/gcc/config/xtensa/xtensa.h
@@ -66,10 +66,9 @@ along with GCC; see the file COPYING3.  If not see
 #define TARGET_LOOPS           XCHAL_HAVE_LOOPS
 #define TARGET_WINDOWED_ABI    (XSHAL_ABI == XTHAL_ABI_WINDOWED)
 #define TARGET_DEBUG           XCHAL_HAVE_DEBUG
+#define TARGET_L32R            XCHAL_HAVE_L32R
 
-#define TARGET_DEFAULT \
-  ((XCHAL_HAVE_L32R    ? 0 : MASK_CONST16) |                           \
-   MASK_SERIALIZE_VOLATILE)
+#define TARGET_DEFAULT (MASK_SERIALIZE_VOLATILE)
 
 #ifndef HAVE_AS_TLS
 #define HAVE_AS_TLS 0
@@ -362,6 +361,12 @@ extern char 
xtensa_hard_regno_mode_ok[][FIRST_PSEUDO_REGISTER];
 /* Base register for access to arguments of the function.  */
 #define ARG_POINTER_REGNUM (GP_REG_FIRST + 17)
 
+/* Hard frame pointer is neither frame nor arg pointer.
+   The definitions are here because actual hard frame pointer register
+   definition is not a preprocessor constant.  */
+#define HARD_FRAME_POINTER_IS_FRAME_POINTER 0
+#define HARD_FRAME_POINTER_IS_ARG_POINTER 0
+
 /* For now we don't try to use the full set of boolean registers.  Without
    software pipelining of FP operations, there's not much to gain and it's
    a real pain to get them reloaded.  */
-- 
2.1.4