[PATCH 1/2] Allow folding all statements.

This patch allows users of the substitute_and_fold_engine to
enable folding all statements.  It is now enabled for VRP which
is needed for the match.pd pattern in patch 2/2.

The loop versioning pass was missing one case when
deconstructing addresses that would only be triggered after
this patch for me:
It could handle addition and subsequent convert/nop but not
a convert/nop directly.  This would cause the hash to be
calculated differently and, in turn, cause the pass to miss
a versioning opportunity.  Fixed this by adding the missing
case.

--

gcc/ChangeLog:

2019-08-26  Robin Dapp  <rdapp@linux.ibm.com>

        * gimple-loop-versioning.cc (loop_versioning::record_address_fragment):
        Add nop_convert case.
        * tree-ssa-propagate.c (substitute_and_fold_dom_walker::before_dom_children):
        Fold all statements if requested.
        * tree-ssa-propagate.h (class substitute_and_fold_engine):
        Allow to fold all statements.
        * tree-vrp.c (class vrp_folder):
        Let substitute_and_fold_engine fold all statements.

From-SVN: r274923

1 files changed, 6 insertions, 0 deletions

diff --git a/gcc/gimple-loop-versioning.cc b/gcc/gimple-loop-versioning.cc
index 8fa1948..35344b7 100644
--- a/gcc/gimple-loop-versioning.cc
+++ b/gcc/gimple-loop-versioning.cc
@@ -1266,6 +1266,12 @@ loop_versioning::record_address_fragment (gimple *stmt,
 		  continue;
 		}
 	    }
+	  if (CONVERT_EXPR_CODE_P (code))
+	    {
+	      tree op1 = gimple_assign_rhs1 (assign);
+	      address->terms[i].expr = strip_casts (op1);
+	      continue;
+	    }
 	}
       i += 1;
     }