Fix a thinko in strength reduction. I was checking the type of the
wrong operand to determine whether address arithmetic should be used in
replacing expressions. This produced a spurious POINTER_PLUS_EXPR when
an address was converted to an unsigned long and back again.
Bootstrapped and tested on powerpc64-unknown-linux-gnu with no new
regressions. Ok for trunk?
Thanks,
Bill
gcc:
2012-08-09 Bill Schmidt <wschm...@linux.vnet.ibm.com>
PR middle-end/54211
* gimple-ssa-strength-reduction.c (analyze_candidates_and_replace):
Use cand_type to determine whether pointer arithmetic will be generated.
gcc/testsuite:
2012-08-09 Bill Schmidt <wschm...@linux.vnet.ibm.com>
PR middle-end/54211
* gcc.dg/tree-ssa/pr54211.c: New test.
Index: gcc/testsuite/gcc.dg/tree-ssa/pr54211.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/pr54211.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/pr54211.c (revision 0)
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+
+int a, b;
+unsigned char e;
+void fn1 ()
+{
+ unsigned char *c=0;
+ for (;; a++)
+ {
+ unsigned char d = *(c + b);
+ for (; &e<&d; c++)
+ goto Found_Top;
+ }
+Found_Top:
+ if (0)
+ goto Empty_Bitmap;
+ for (;; a++)
+ {
+ unsigned char *e = c + b;
+ for (; c < e; c++)
+ goto Found_Bottom;
+ c -= b;
+ }
+Found_Bottom:
+Empty_Bitmap:
+ ;
+}
Index: gcc/gimple-ssa-strength-reduction.c
===================================================================
--- gcc/gimple-ssa-strength-reduction.c (revision 190260)
+++ gcc/gimple-ssa-strength-reduction.c (working copy)
@@ -2534,7 +2534,7 @@ analyze_candidates_and_replace (void)
/* Determine whether we'll be generating pointer arithmetic
when replacing candidates. */
address_arithmetic_p = (c->kind == CAND_ADD
- && POINTER_TYPE_P (TREE_TYPE (c->base_expr)));
+ && POINTER_TYPE_P (c->cand_type));
/* If all candidates have already been replaced under other
interpretations, nothing remains to be done. */
