Allow more complex call replacements in gimple-fold.c

An upcoming patch adds a match.pd rule that folds pow(pow(x,y),z)
to pow(x,y*z).  This fold can reuse the existing pow gimple statement
and simply replace the operands with x and y*z.  However, the y*z
itself requires a separate gimple statement and the code wasn't
prepared to handle that.

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* gimple-fold.c (replace_stmt_with_simplification): Don't allow
	new statements to be inserted if inplace.  Allow calls to have
	nonempty sequences.

From-SVN: r229371

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f7371b0dc79c8d7bce23be3ea6c725a8ad87388f..b35b201b0f7749dc8d1f221a55730e4b473a7cd6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2015-10-26  Richard Sandiford  <richard.sandiford@arm.com>
+
+       * gimple-fold.c (replace_stmt_with_simplification): Don't allow
+       new statements to be inserted if inplace.  Allow calls to have
+       nonempty sequences.
+
 2015-10-26  Richard Biener  <rguenther@suse.de>
 
        * tree-object-size.c: Remove builtins.h include, include tree-cfg.h.

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 1869c097d7fb73e39dbbe4e7a1b99938e906d691..392738d7f677f1fcec63ccf34af891f17c53e2bb 100644 (file)
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -3289,6 +3289,11 @@ replace_stmt_with_simplification (gimple_stmt_iterator *gsi,
          && !has_use_on_stmt (ops[2], stmt)))
     return false;
 
+  /* Don't insert new statements when INPLACE is true, even if we could
+     reuse STMT for the final statement.  */
+  if (inplace && !gimple_seq_empty_p (*seq))
+    return false;
+
   if (gcond *cond_stmt = dyn_cast <gcond *> (stmt))
     {
       gcc_assert (rcode.is_tree_code ());
@@ -3365,7 +3370,14 @@ replace_stmt_with_simplification (gimple_stmt_iterator *gsi,
        }
       if (i < 3)
        gcc_assert (ops[i] == NULL_TREE);
-      gcc_assert (gimple_seq_empty_p (*seq));
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       {
+         fprintf (dump_file, "gimple_simplified to ");
+         if (!gimple_seq_empty_p (*seq))
+           print_gimple_seq (dump_file, *seq, 0, TDF_SLIM);
+         print_gimple_stmt (dump_file, gsi_stmt (*gsi), 0, TDF_SLIM);
+       }
+      gsi_insert_seq_before (gsi, *seq, GSI_SAME_STMT);
       return true;
     }
   else if (!inplace)