Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2016-07-21 Richard Biener <rguent...@suse.de>
PR tree-optimization/71947
* tree-vrp.c (extract_range_from_assert): Singleton symbolic
ranges have useful limit_vr information.
* gcc.dg/tree-ssa/vrp102.c: New testcase.
Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c (revision 238469)
--- gcc/tree-vrp.c (working copy)
*************** extract_range_from_assert (value_range *
*** 1513,1522 ****
limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
/* LIMIT's range is only interesting if it has any useful information. */
! if (limit_vr
! && (limit_vr->type == VR_UNDEFINED
! || limit_vr->type == VR_VARYING
! || symbolic_range_p (limit_vr)))
limit_vr = NULL;
/* Initially, the new range has the same set of equivalences of
--- 1514,1526 ----
limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
/* LIMIT's range is only interesting if it has any useful information. */
! if (! limit_vr
! || limit_vr->type == VR_UNDEFINED
! || limit_vr->type == VR_VARYING
! || (symbolic_range_p (limit_vr)
! && ! (limit_vr->type == VR_RANGE
! && (limit_vr->min == limit_vr->max
! || operand_equal_p (limit_vr->min, limit_vr->max, 0)))))
limit_vr = NULL;
/* Initially, the new range has the same set of equivalences of
Index: gcc/testsuite/gcc.dg/tree-ssa/vrp102.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/vrp102.c (revision 0)
--- gcc/testsuite/gcc.dg/tree-ssa/vrp102.c (working copy)
***************
*** 0 ****
--- 1,18 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -fno-tree-dominator-opts -fdump-tree-vrp1" } */
+
+ int f(int x, int y)
+ {
+ int ret;
+ if (x == y)
+ ret = x ^ y;
+ else
+ ret = 1;
+
+ return ret;
+ }
+
+ /* We should have computed x ^ y as zero and propagated the result into the
+ PHI feeding the result. */
+
+ /* { dg-final { scan-tree-dump "ret_\[0-9\]+ = PHI <\[01\]\\\(\[0-9\]+\\\),
\[01\]\\\(\[0-9\]+\\\)>" "vrp1" } } */
