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Re: [PATCH]: fix for PR middle-end/38250


Hi,

re-organized.
 
> On Wed, Nov 26, 2008 at 4:43 PM, Tomas Bily <tbily@suse.cz> wrote:
> > Hi,
> >
> > The PR is caused by two problems:
> >
> > In tree-loop-distribution.c (generate_memset_zero):
> >
> > 1. It can be DR_STEP(dr) NULL. But it is passed into fold_build2 that
> > expect two non null expressions.
> >
> > 2. If program flow goes to end: due to goto then temporary variables created
> > during force_gimple_operand are added to referenced vars. But this variables
> > have not def bb. So later checks fails.
> >
> > This patch add check for DR_STEP and remove newly generated stmts if
> > generating of memset fails.
> >
> > Tested and bootsraped on x86_64-unknown-linux-gnu.
> >
> > OK for mainline ?
> 
> Please re-organize the function instead to not add the stmts until needed.
> This looks trivially possible.
> 
> Thanks,
> Richard.
> 
> > Greetings
> > Tomas
> >

Tested and bootsraped on x86_64-unknown-linux-gnu.
OK for mainline ?

Greetings
Tomas

 Changelog:

        PR middle-end/38250
        * tree-loop-distribution.c (build_size_arg): New function.
        (generate_memset_zero): Checks if DR_STEP(de) is NULL. 
        Reorganized generating of stmts.

Index: tree-loop-distribution.c
===================================================================
--- tree-loop-distribution.c	(revision 142159)
+++ tree-loop-distribution.c	(working copy)
@@ -216,13 +216,30 @@ generate_loops_for_partition (struct loo
   return true;
 }
 
+/* Build size argument.  */
+
+static inline tree
+build_size_arg (tree nb_iter, tree op, gimple_seq* stmt_list)
+{
+    tree nb_bytes;
+    gimple_seq stmts = NULL;
+
+    nb_bytes = fold_build2 (MULT_EXPR, TREE_TYPE (nb_iter),
+			    nb_iter, TYPE_SIZE_UNIT (TREE_TYPE (op)));
+    nb_bytes = force_gimple_operand (nb_bytes, &stmts, true, NULL);
+    gimple_seq_add_seq (stmt_list, stmts);
+
+    return nb_bytes;
+}
+
 /* Generate a call to memset.  Return true when the operation succeeded.  */
 
 static bool
 generate_memset_zero (gimple stmt, tree op0, tree nb_iter,
 		      gimple_stmt_iterator bsi)
 {
-  tree t, nb_bytes, addr_base;
+  tree t, addr_base;
+  tree nb_bytes = NULL;
   bool res = false;
   gimple_seq stmts = NULL, stmt_list = NULL;
   gimple fn_call;
@@ -231,15 +248,13 @@ generate_memset_zero (gimple stmt, tree 
   ssa_op_iter iter;
   struct data_reference *dr = XCNEW (struct data_reference);
 
-  nb_bytes = fold_build2 (MULT_EXPR, TREE_TYPE (nb_iter),
-			  nb_iter, TYPE_SIZE_UNIT (TREE_TYPE (op0)));
-  nb_bytes = force_gimple_operand (nb_bytes, &stmts, true, NULL);
-  gimple_seq_add_seq (&stmt_list, stmts);
-
   DR_STMT (dr) = stmt;
   DR_REF (dr) = op0;
   dr_analyze_innermost (dr);
 
+  if (!DR_STEP (dr))
+    goto end;
+
   /* Test for a positive stride, iterating over every element.  */
   if (integer_zerop (fold_build2 (MINUS_EXPR, integer_type_node, DR_STEP (dr),
 				  TYPE_SIZE_UNIT (TREE_TYPE (op0)))))
@@ -253,6 +268,7 @@ generate_memset_zero (gimple stmt, tree 
 				       TYPE_SIZE_UNIT (TREE_TYPE (op0)),
 				       DR_STEP (dr))))
     {
+      nb_bytes = build_size_arg (nb_iter, op0, &stmt_list);
       addr_base = size_binop (PLUS_EXPR, DR_OFFSET (dr), DR_INIT (dr));
       addr_base = fold_build2 (MINUS_EXPR, sizetype, addr_base, nb_bytes);
       addr_base = force_gimple_operand (addr_base, &stmts, true, NULL);
@@ -272,6 +288,8 @@ generate_memset_zero (gimple stmt, tree 
   fntype = TREE_TYPE (fndecl);
   fn = build1 (ADDR_EXPR, build_pointer_type (fntype), fndecl);
 
+  if (!nb_bytes)
+      nb_bytes = build_size_arg (nb_iter, op0, &stmt_list);
   fn_call = gimple_build_call (fn, 3, mem, integer_zero_node, nb_bytes);
   gimple_seq_add_stmt (&stmt_list, fn_call);
 
Index: testsuite/gcc.dg/tree-ssa/pr38250.c
===================================================================
--- testsuite/gcc.dg/tree-ssa/pr38250.c	(revision 0)
+++ testsuite/gcc.dg/tree-ssa/pr38250.c	(revision 0)
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-loop-distribution" } */
+
+typedef long unsigned int size_t;
+typedef struct   {
+          long dat[2];
+} gsl_complex_long_double;
+typedef struct {
+ size_t size;
+ size_t stride;
+ long *data;
+} gsl_vector_complex_long_double;
+
+void gsl_vector_complex_long_double_set_zero (gsl_vector_complex_long_double * v) 
+{
+ long * const data = v->data;
+ const size_t n = v->size;
+ const size_t stride = v->stride;
+ const gsl_complex_long_double zero = { { 0,0} } ;
+ size_t i;
+ for (i = 0; i < n; i++)     
+  *(gsl_complex_long_double *) (data + 2 * i * stride) = zero;
+}
+


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