Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2015-11-10 Richard Biener <rguent...@suse.de>
PR tree-optimization/68240
* tree-ssa-sccvn.c (cond_stmts_equal_p): Handle commutative compares
properly.
(visit_phi): For PHIs with just a single executable edge
take its value directly.
(expressions_equal_p): Handle VN_TOP properly.
* gcc.dg/torture/pr68240.c: New testcase.
Index: gcc/testsuite/gcc.dg/torture/pr68240.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr68240.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr68240.c (working copy)
***************
*** 0 ****
--- 1,12 ----
+ /* { dg-do compile } */
+
+ int a, b, f;
+
+ void
+ fn1 ()
+ {
+ int c = 1, d, e = 1;
+ a = 1;
+ for (; f;)
+ b = (c && (d = (e && a)));
+ }
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c (revision 230020)
--- gcc/tree-ssa-sccvn.c (working copy)
*************** cond_stmts_equal_p (gcond *cond1, gcond
*** 2760,2770 ****
else
return false;
! if (! expressions_equal_p (vn_valueize (lhs1), vn_valueize (lhs2))
! || ! expressions_equal_p (vn_valueize (rhs1), vn_valueize (rhs2)))
! return false;
!
! return true;
}
/* Compare two phi entries for equality, ignoring VN_TOP arguments. */
--- 2806,2820 ----
else
return false;
! lhs1 = vn_valueize (lhs1);
! rhs1 = vn_valueize (rhs1);
! lhs2 = vn_valueize (lhs2);
! rhs2 = vn_valueize (rhs2);
! return ((expressions_equal_p (lhs1, lhs2)
! && expressions_equal_p (rhs1, rhs2))
! || (commutative_tree_code (code1)
! && expressions_equal_p (lhs1, rhs2)
! && expressions_equal_p (rhs1, lhs2)));
}
/* Compare two phi entries for equality, ignoring VN_TOP arguments. */
*************** visit_phi (gimple *phi)
*** 3379,3384 ****
--- 3428,3434 ----
tree result;
tree sameval = VN_TOP;
bool allsame = true;
+ unsigned n_executable = 0;
/* TODO: We could check for this in init_sccvn, and replace this
with a gcc_assert. */
*************** visit_phi (gimple *phi)
*** 3394,3399 ****
--- 3444,3450 ----
{
tree def = PHI_ARG_DEF_FROM_EDGE (phi, e);
+ ++n_executable;
if (TREE_CODE (def) == SSA_NAME)
def = SSA_VAL (def);
if (def == VN_TOP)
*************** visit_phi (gimple *phi)
*** 3408,3416 ****
}
/* If none of the edges was executable or all incoming values are
! undefined keep the value-number at VN_TOP. */
! if (sameval == VN_TOP)
! return set_ssa_val_to (PHI_RESULT (phi), VN_TOP);
/* First see if it is equivalent to a phi node in this block. We prefer
this as it allows IV elimination - see PRs 66502 and 67167. */
--- 3459,3469 ----
}
/* If none of the edges was executable or all incoming values are
! undefined keep the value-number at VN_TOP. If only a single edge
! is exectuable use its value. */
! if (sameval == VN_TOP
! || n_executable == 1)
! return set_ssa_val_to (PHI_RESULT (phi), sameval);
/* First see if it is equivalent to a phi node in this block. We prefer
this as it allows IV elimination - see PRs 66502 and 67167. */
*************** expressions_equal_p (tree e1, tree e2)
*** 4610,4615 ****
--- 4663,4672 ----
if (e1 == e2)
return true;
+ /* If either one is VN_TOP consider them equal. */
+ if (e1 == VN_TOP || e2 == VN_TOP)
+ return true;
+
/* If only one of them is null, they cannot be equal. */
if (!e1 || !e2)
return false;
