[PATCH] Fix PR52170

[Richard Guenther]

We can enter simplify_plus_minus with integer vector mode operands
and thus we shouldn't use constm1_rtx when canonicalizing ~a but
CONSTM1_RTX (mode).

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2012-02-08  Richard Guenther  <rguent...@suse.de>

        PR rtl-optimization/52170
        * simplify-rtx.c (simplify_plus_minus): Use CONSTM1_RTX to
        properly handle integer vector modes.

        * gcc.dg/torture/pr52170.c: New testcase.

Index: gcc/simplify-rtx.c
===================================================================
*** gcc/simplify-rtx.c  (revision 183997)
--- gcc/simplify-rtx.c  (working copy)
*************** simplify_plus_minus (enum rtx_code code,
*** 3947,3953 ****
              /* ~a -> (-a - 1) */
              if (n_ops != 7)
                {
!                 ops[n_ops].op = constm1_rtx;
                  ops[n_ops++].neg = this_neg;
                  ops[i].op = XEXP (this_op, 0);
                  ops[i].neg = !this_neg;
--- 3947,3953 ----
              /* ~a -> (-a - 1) */
              if (n_ops != 7)
                {
!                 ops[n_ops].op = CONSTM1_RTX (mode);
                  ops[n_ops++].neg = this_neg;
                  ops[i].op = XEXP (this_op, 0);
                  ops[i].neg = !this_neg;
Index: gcc/testsuite/gcc.dg/torture/pr52170.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr52170.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr52170.c      (revision 0)
***************
*** 0 ****
--- 1,17 ----
+ /* { dg-do compile } */
+ 
+ typedef unsigned char uint8_t ;
+ typedef unsigned long uint32_t;
+ void f0a(uint32_t * result, uint32_t * arg1)
+ {
+   int idx;
+   for (idx=0;idx<96;idx += 1)
+     {
+       uint8_t temp_5;
+       uint8_t temp_6;
+ 
+       temp_5 = ~(*arg1);
+       temp_6 = (*arg1) + 1 - temp_5;
+       result[idx] = temp_6;
+     }
+ }