[backport from gcc-4.7/trunk <mikpe@it.uu.se>]

Date: Tue, 6 Dec 2011 20:17:04 -0800
Subject: [PATCH] Fix PR middle-end/45416, missing opt for (a&(1<<C))!=0 to (a>>C)&1
From: Andrew Pinski <pinskia at gmail dot com>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

Hi,
  After SSA-expand, the code which did the optimization for
(a&(1<<C))!=0 to (a>>C)&1 became not working because BIT_AND_EXPR
would no longer be in there.  This patch fixes the problem by using
get_def_for_expr to get the BIT_AND_EXPR.

OK?  Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Thanks,
Andrew Pinski

gcc/

2011-12-07  Andrew Pinski  <apinski@cavium.com>

	PR middle-end/45416
	* expr.c (do_store_flag): Rewrite code that looks for BIT_AND_EXPR for
	SSA-expand.

gcc/testsuite/

2011-12-07  Andrew Pinski  <apinski@cavium.com>

	PR middle-end/45416
	* gcc.dg/pr45416.c: New testcase.

--- gcc-4.6.2/gcc/expr.c.~1~	2011-08-10 11:17:32.000000000 +0200
+++ gcc-4.6.2/gcc/expr.c	2011-12-17 15:49:38.000000000 +0100
@@ -10098,15 +10098,22 @@ do_store_flag (sepops ops, rtx target, e
      so we just call into the folder and expand its result.  */
 
   if ((code == NE || code == EQ)
-      && TREE_CODE (arg0) == BIT_AND_EXPR && integer_zerop (arg1)
-      && integer_pow2p (TREE_OPERAND (arg0, 1))
+      && integer_zerop (arg1)
       && (TYPE_PRECISION (ops->type) != 1 || TYPE_UNSIGNED (ops->type)))
     {
-      tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
-      return expand_expr (fold_single_bit_test (loc,
-						code == NE ? NE_EXPR : EQ_EXPR,
-						arg0, arg1, type),
-			  target, VOIDmode, EXPAND_NORMAL);
+      gimple srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR);
+      if (srcstmt
+	  && integer_pow2p (gimple_assign_rhs2 (srcstmt)))
+	{
+	  enum tree_code tcode = code == NE ? NE_EXPR : EQ_EXPR;
+	  tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
+	  tree temp = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (arg1),
+				       gimple_assign_rhs1 (srcstmt),
+				       gimple_assign_rhs2 (srcstmt));
+	  temp = fold_single_bit_test (loc, tcode, temp, arg1, type);
+	  if (temp)
+	    return expand_expr (temp, target, VOIDmode, EXPAND_NORMAL);
+	}
     }
 
   if (! get_subtarget (target)
--- gcc-4.6.2/gcc/testsuite/gcc.dg/pr45416.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.2/gcc/testsuite/gcc.dg/pr45416.c	2011-12-17 15:49:38.000000000 +0100
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int foo(long long a)
+{
+   if (a & (long long) 0x400)
+      return 1;
+   return 0;
+}
+
+/* { dg-final { scan-assembler "andl" { target i?86-*-linux* x86_64-*-linux* } } } " */
+/* { dg-final { scan-assembler-not "setne" { target i?86-*-linux* x86_64-*-linux* } } }" */
+/* { dg-final { scan-assembler "and" { target arm*-*-* } } }" */
+/* { dg-final { scan-assembler-not "moveq" { target arm*-*-* } } }" */