[PATCH] Fix fold_binary RROTATE_EXPR opts (PR middle-end/71693)

[Jakub Jelinek]

Hi!

This issue is latent on the trunk/6.2, fails with checking in 5.x/4.9.
As usually in fold_*_loc, arg0/arg1 is STRIP_NOPS op0/op1, so might have
incompatible type, so we need to convert it to the right type first
before optimizing.

Bootstrapped/regtested on x86_64-linux/i686-linux, ok everywhere?

2016-06-29  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/71693
        * fold-const.c (fold_binary_loc) <case RROTATE_EXPR>: Cast
        TREE_OPERAND (arg0, 0) and TREE_OPERAND (arg0, 1) to type
        first when permuting bitwise operation with rotate.  Cast
        TREE_OPERAND (arg0, 0) to type when cancelling two rotations.

        * gcc.c-torture/compile/pr71693.c: New test.

--- gcc/fold-const.c.jj 2016-06-14 12:17:20.530282919 +0200
+++ gcc/fold-const.c    2016-06-29 16:39:15.175562715 +0200
@@ -10294,11 +10294,15 @@ fold_binary_loc (location_t loc,
              || TREE_CODE (arg0) == BIT_IOR_EXPR
              || TREE_CODE (arg0) == BIT_XOR_EXPR)
          && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
-       return fold_build2_loc (loc, TREE_CODE (arg0), type,
-                           fold_build2_loc (loc, code, type,
-                                        TREE_OPERAND (arg0, 0), arg1),
-                           fold_build2_loc (loc, code, type,
-                                        TREE_OPERAND (arg0, 1), arg1));
+       {
+         tree arg00 = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
+         tree arg01 = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 1));
+         return fold_build2_loc (loc, TREE_CODE (arg0), type,
+                                 fold_build2_loc (loc, code, type,
+                                                  arg00, arg1),
+                                 fold_build2_loc (loc, code, type,
+                                                  arg01, arg1));
+       }
 
       /* Two consecutive rotates adding up to the some integer
         multiple of the precision of the type can be ignored.  */
@@ -10307,7 +10311,7 @@ fold_binary_loc (location_t loc,
          && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
          && wi::umod_trunc (wi::add (arg1, TREE_OPERAND (arg0, 1)),
                             prec) == 0)
-       return TREE_OPERAND (arg0, 0);
+       return fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
 
       return NULL_TREE;
 
--- gcc/testsuite/gcc.c-torture/compile/pr71693.c.jj    2016-06-29 
16:39:15.175562715 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr71693.c       2016-06-29 
16:39:15.175562715 +0200
@@ -0,0 +1,10 @@
+/* PR middle-end/71693 */
+
+unsigned short v;
+
+void
+foo (int x)
+{
+  v = ((((unsigned short) (0x0001 | (x & 0x0070) | 0x0100) & 0x00ffU) << 8)
+       | (((unsigned short) (0x0001 | (x & 0x0070) | 0x0100) >> 8) & 0x00ffU));
+}

        Jakub