[Trivial] tree-sra.c: A few comment fixes/additions.

	* tree-sra.c (scalarizable_type_p): Comment variable-length arrays.
	(completely_scalarize): Comment zero-length arrays.
	(get_access_replacement): Correct comment re. precondition.

From-SVN: r229577

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e6b8b27bc6f7de2f4f3961b0e88514ec78e76b39..7178c5aeec33ea7df6822ebc8b4759754a30a7c2 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-10-30  Alan Lawrence  <alan.lawrence@arm.com>
+
+       * tree-sra.c (scalarizable_type_p): Comment variable-length arrays.
+       (completely_scalarize): Comment zero-length arrays.
+       (get_access_replacement): Correct comment re. precondition.
+
 2015-10-30  Venkataramanan Kumar  <venkataramanan.kumar@amd.com>
 
        * config/i386/i386.c (get_builtin_code_for_version): Set priority

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index b6172cd220c3504e1ccbf6d6e21a6cbddee2f8a8..82c58f0ae3a71dcace2f9c39e6c76d4392108c05 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -956,6 +956,7 @@ scalarizable_type_p (tree type)
        ;
       else if ((tree_to_shwi (TYPE_SIZE (type)) <= 0)
               || !tree_fits_shwi_p (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
+       /* Variable-length array, do not allow scalarization.  */
        return false;
 
       tree elem = TREE_TYPE (type);
@@ -1005,6 +1006,7 @@ completely_scalarize (tree base, tree decl_type, HOST_WIDE_INT offset, tree ref)
        tree minidx = TYPE_MIN_VALUE (TYPE_DOMAIN (decl_type));
        gcc_assert (TREE_CODE (minidx) == INTEGER_CST);
        tree maxidx = TYPE_MAX_VALUE (TYPE_DOMAIN (decl_type));
+       /* Skip (some) zero-length arrays; others have MAXIDX == MINIDX - 1.  */
        if (maxidx)
          {
            gcc_assert (TREE_CODE (maxidx) == INTEGER_CST);
@@ -2146,7 +2148,7 @@ create_access_replacement (struct access *access)
   return repl;
 }
 
-/* Return ACCESS scalar replacement, create it if it does not exist yet.  */
+/* Return ACCESS scalar replacement, which must exist.  */
 
 static inline tree
 get_access_replacement (struct access *access)