2005-10-05 Steven Bosscher <stevenb@suse.de>

gcc/
	PR tree-optimization/23049
	* tree-ssa-dom.c (thread_across_edge): Make sure that the condition
	of a COND_EXPR is folded before calling fold on the whole rhs of a
	conditional assignment.
	* doc/tree-ssa.texi: Update the GIMPLE grammar for a valid rhs to
	document that a COND_EXPR may appear there.

testsuite/
	* gcc.dg/pr23049.c: New test.

	* gcc.dg/ucnid-4.c: Fix test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@104938 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 229ef27..9003d0d 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2005-10-05  Steven Bosscher  <stevenb@suse.de>
+
+       PR tree-optimization/23049
+       * tree-ssa-dom.c (thread_across_edge): Make sure that the condition
+       of a COND_EXPR is folded before calling fold on the whole rhs of a
+       conditional assignment.
+       * doc/tree-ssa.texi: Update the GIMPLE grammar for a valid rhs to
+       document that a COND_EXPR may appear there.
+
 2005-10-03  Diego Novillo  <dnovillo@redhat.com>
 
        PR 23445

diff --git a/gcc/doc/tree-ssa.texi b/gcc/doc/tree-ssa.texi
index cbc08a1..77a2f0a 100644 (file)
--- a/gcc/doc/tree-ssa.texi
+++ b/gcc/doc/tree-ssa.texi
@@ -728,6 +728,10 @@ void f()
                 | RELOP
                         op0 -> val
                         op1 -> val
+               | COND_EXPR
+                       op0 -> condition
+                       op1 -> val
+                       op2 -> val
 @end smallexample
 
 @node Annotations

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6aa6e81..34826bf 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2005-10-05  Steven Bosscher  <stevenb@suse.de>
+
+       * gcc.dg/pr23049.c: New test.
+
+       * gcc.dg/ucnid-4.c: Fix test.
+
 2005-10-03  Diego Novillo  <dnovillo@redhat.com>
 
        PR 23445

diff --git a/gcc/testsuite/gcc.dg/pr23049.c b/gcc/testsuite/gcc.dg/pr23049.c
new file mode 100644 (file)
index 0000000..0a71cec
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr23049.c
@@ -0,0 +1,26 @@
+/* This was an ICE in fold where we tried to fold something like,
+
+     a = 0 == 0 ? 0 : 3988292384
+
+   after doing if-conversion for the vectorizer.  Folding "0 == 0"
+   should have been done before calling fold on the whole rhs of
+   the above expression.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O3 -ftree-vectorize" } */
+
+static unsigned short int crc_table[256];
+void AC3_encode_init(void)
+{
+  unsigned int c, n, k;
+  for(n=0;  n<256; n++)
+  {
+    c = n << 8;
+    for (k = 0; k < 8; k++)
+    {
+      if (c & (1 << 15))
+       c = ((c << 1) & 0xffff) ^ (((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16)) & 0xffff);
+    }
+    crc_table[n] = c;
+  }
+}

diff --git a/gcc/testsuite/gcc.dg/ucnid-4.c b/gcc/testsuite/gcc.dg/ucnid-4.c
index f9bf68e..1fd4925 100644 (file)
--- a/gcc/testsuite/gcc.dg/ucnid-4.c
+++ b/gcc/testsuite/gcc.dg/ucnid-4.c
@@ -1,4 +1,4 @@
-/* { dg-do run */
+/* { dg-do run } */
 /* { dg-xfail-if "" { "powerpc-ibm-aix*" } { "*" } { "" } } */
 /* { dg-options "-std=c99 -fextended-identifiers" } */
 void abort (void);

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 1b78b6d..71dcd4f 100644 (file)
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -666,7 +666,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
      statements.  This does not prevent threading through E->dest.  */
   for (bsi = bsi_start (e->dest); ! bsi_end_p (bsi); bsi_next (&bsi))
     {
-      tree cached_lhs;
+      tree cached_lhs = NULL;
 
       stmt = bsi_stmt (bsi);
 
@@ -705,7 +705,7 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
       else
        {
          /* Copy the operands.  */
-         tree *copy;
+         tree *copy, pre_fold_expr;
          ssa_op_iter iter;
          use_operand_p use_p;
          unsigned int num, i = 0;
@@ -729,12 +729,31 @@ thread_across_edge (struct dom_walk_data *walk_data, edge e)
 
          /* Try to fold/lookup the new expression.  Inserting the
             expression into the hash table is unlikely to help
-            simplify anything later, so just query the hashtable.  */
-         cached_lhs = fold (TREE_OPERAND (stmt, 1));
-         if (TREE_CODE (cached_lhs) != SSA_NAME
-             && !is_gimple_min_invariant (cached_lhs))
-           cached_lhs = lookup_avail_expr (stmt, false);
+            Sadly, we have to handle conditional assignments specially
+            here, because fold expects all the operands of an expression
+            to be folded before the expression itself is folded, but we
+            can't just substitute the folded condition here.  */
+         if (TREE_CODE (TREE_OPERAND (stmt, 1)) == COND_EXPR)
+           {
+             tree cond = COND_EXPR_COND (TREE_OPERAND (stmt, 1));
+             cond = fold (cond);
+             if (cond == boolean_true_node)
+               pre_fold_expr = COND_EXPR_THEN (TREE_OPERAND (stmt, 1));
+             else if (cond == boolean_false_node)
+               pre_fold_expr = COND_EXPR_ELSE (TREE_OPERAND (stmt, 1));
+             else
+               pre_fold_expr = TREE_OPERAND (stmt, 1);
+           }
+         else
+           pre_fold_expr = TREE_OPERAND (stmt, 1);
 
+         if (pre_fold_expr)
+           {
+             cached_lhs = fold (pre_fold_expr);
+             if (TREE_CODE (cached_lhs) != SSA_NAME
+                 && !is_gimple_min_invariant (cached_lhs))
+               cached_lhs = lookup_avail_expr (stmt, false);
+           }
 
          /* Restore the statement's original uses/defs.  */
          i = 0;