mmix: Define MAX_FIXED_MODE_SIZE

Besides this commit working as a release-branch fix for the
PR, code inspection shows slightly better code for TImode
libgcc functions, and a modified
gcc.c-torture/execute/arith-rand-ll.c (basically s/long
long/__int128 and cutting out the non-128-bit cases) shows a
1.4% improvement.  (Coremark code is identical, as
expected.)

	PR middle-end/120935
	* config/mmix/mmix.h (MAX_FIXED_MODE_SIZE): Define.

Co-authored-by: Pietro Monteiro <pietro@sociotechnical.xyz>
Signed-off-by: Pietro Monteiro <pietro@sociotechnical.xyz>

diff --git a/gcc/config/mmix/mmix.h b/gcc/config/mmix/mmix.h
index 44669e195b4ac6676339d622d01cf0cbfec88fa2..354783eccedda885018370ac056d715b2c81444d 100644 (file)
--- a/gcc/config/mmix/mmix.h
+++ b/gcc/config/mmix/mmix.h
@@ -184,6 +184,9 @@ struct GTY(()) machine_function
 /* The lower bits are ignored.  */
 #define STRICT_ALIGNMENT 1
 
+/* With the default, (64 bits), most things still work, but code for
+   e.g. __int128 will be suboptimal. */
+#define MAX_FIXED_MODE_SIZE (2 * BITS_PER_WORD)
 
 /* Node: Type Layout */