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2008-04-29 Richard Guenther <rguenther@suse.de>
authorrguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Tue, 29 Apr 2008 15:59:43 +0000 (15:59 +0000)
committerrguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Tue, 29 Apr 2008 15:59:43 +0000 (15:59 +0000)
PR middle-end/15255
* fold-const.c (fold_binary): Fold (A + A) * C to A * 2*C.

* gcc.dg/fold-plusmult.c: New testcase.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@134798 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog
gcc/fold-const.c
gcc/testsuite/ChangeLog
gcc/testsuite/gcc.dg/fold-plusmult.c [new file with mode: 0644]

index e261305..b5ae15e 100644 (file)
@@ -1,5 +1,10 @@
 2008-04-29  Richard Guenther  <rguenther@suse.de>
 
+       PR middle-end/15255
+       * fold-const.c (fold_binary): Fold (A + A) * C to A * 2*C.
+
+2008-04-29  Richard Guenther  <rguenther@suse.de>
+
        * tree-ssa-alias.c (finalize_ref_all_pointers): Remove.
        (compute_may_aliases): Do not call finalize_ref_all_pointers.
        (compute_flow_insensitive_aliasing): Do not treat
index aae2037..b4645ca 100644 (file)
@@ -10154,6 +10154,17 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
            return fold_build2 (LSHIFT_EXPR, type, op1,
                                TREE_OPERAND (arg0, 1));
 
+         /* (A + A) * C -> A * 2 * C  */
+         if (TREE_CODE (arg0) == PLUS_EXPR
+             && TREE_CODE (arg1) == INTEGER_CST
+             && operand_equal_p (TREE_OPERAND (arg0, 0),
+                                 TREE_OPERAND (arg0, 1), 0))
+           return fold_build2 (MULT_EXPR, type,
+                               omit_one_operand (type, TREE_OPERAND (arg0, 0),
+                                                 TREE_OPERAND (arg0, 1)),
+                               fold_build2 (MULT_EXPR, type,
+                                            build_int_cst (type, 2) , arg1));
+
          strict_overflow_p = false;
          if (TREE_CODE (arg1) == INTEGER_CST
              && 0 != (tem = extract_muldiv (op0, arg1, code, NULL_TREE,
index f2b69e9..dd8b3ae 100644 (file)
@@ -1,5 +1,10 @@
 2008-04-29  Richard Guenther  <rguenther@suse.de>
 
+       PR middle-end/15255
+       * gcc.dg/fold-plusmult.c: New testcase.
+
+2008-04-29  Richard Guenther  <rguenther@suse.de>
+
        PR middle-end/36077
        * gcc.c-torture/execute/pr36077.c: New testcase.
 
diff --git a/gcc/testsuite/gcc.dg/fold-plusmult.c b/gcc/testsuite/gcc.dg/fold-plusmult.c
new file mode 100644 (file)
index 0000000..d584b95
--- /dev/null
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-original" } */
+
+int test1 (int a)
+{
+  return 2*a + 2*a;
+}
+
+int test2 (int a)
+{
+  return (a + a)*2;
+}
+
+/* { dg-final { scan-tree-dump-times "<a> \\\* 4" 2 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */