* stor-layout.c (layout_type): Use FORCE_STRUCT_BLK.

	* tm.texi (FORCE_STRUCT_BLK): Document.
	* config/c4x/c4x.h (FORCE_STRUCT_BLK): New macro.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@31385 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0a6a8a6..cc95cab 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2000-01-13  Michael Hayes  <m.hayes@elec.canterbury.ac.nz>
+
+       * stor-layout.c (layout_type): Use FORCE_STRUCT_BLK.
+       * tm.texi (FORCE_STRUCT_BLK): Document.
+       * config/c4x/c4x.h (FORCE_STRUCT_BLK): New macro.
+
 Wed Jan 12 23:12:47 2000  Hans-Peter Nilsson  <hp@axis.com>
 
        * config/ns32k/ns32k.md: Revert Jan 9 change.

diff --git a/gcc/config/c4x/c4x.h b/gcc/config/c4x/c4x.h
index b6b43be..470d657 100644 (file)
--- a/gcc/config/c4x/c4x.h
+++ b/gcc/config/c4x/c4x.h
@@ -352,6 +352,10 @@ extern const char *c4x_rpts_cycles_string, *c4x_cpu_version_string;
 #define TARGET_FLOAT_FORMAT    C4X_FLOAT_FORMAT
 #define MAX_FIXED_MODE_SIZE    64 /* HImode.  */
 
+/* If a structure has a floating point field then force structure
+   to have BLKMODE.  */
+#define STRUCT_FORCE_BLK(FIELD) (TREE_CODE (TREE_TYPE (FIELD)) == REAL_TYPE)
+
 /* Number of bits in the high and low parts of a two stage
    load of an immediate constant.  */
 #define BITS_PER_HIGH 16

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index e9c3740..455152f 100644 (file)
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -1057,6 +1057,13 @@ layout_type (type)
                 register instead of forcing it to live in the stack.  */
              if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
                mode = DECL_MODE (field);
+
+#ifdef STRUCT_FORCE_BLK
+             /* With some targets, eg. c4x, it is sub-optimal
+                to access an aligned BLKmode structure as a scalar.  */
+             if (mode == VOIDmode && STRUCT_FORCE_BLK (field))
+                 goto record_lose;
+#endif /* STRUCT_FORCE_BLK  */
            }
 
          if (mode != VOIDmode)

diff --git a/gcc/tm.texi b/gcc/tm.texi
index 385a0dc..dac44ae 100644 (file)
--- a/gcc/tm.texi
+++ b/gcc/tm.texi
@@ -413,6 +413,15 @@ if any, in all upper-case letters.  For example, it might be @samp{GCC}
 or @samp{BINUTILS}.  If the package is part of the a vendor-supplied
 operating system, code the component name as @samp{0}.
 
+@findex STRUCT_FORCE_BLK
+@item STRUCT_FORCE_BLK (@var{field})
+Return 1 if a structure containing @var{field} should be accessed using
+@code{BLKMODE}.
+
+Normally, this is not needed.  See the file @file{c4x.h} for an example
+of how to use this macro to prevent a structure having a floating point
+field from being accessed in an integer mode.
+
 
 For example, here is the definition used for VAX/VMS: