re PR tree-optimization/57993 (ICE: verify_ssa failed (definition in block n…

re PR tree-optimization/57993 (ICE: verify_ssa failed (definition in block n does not dominate use in block m))

gcc:

2013-07-29  Bill Schmidt  <wschmidt@vnet.linux.ibm.com>

	PR tree-optimization/57993
	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Record
	replaced statement in the candidate table.
	(phi_add_costs): Return infinite cost when the hidden basis does
	not dominate all phis on which the candidate is dependent.
	(replace_one_candidate): Record replaced statement in the
	candidate table.

gcc/testsuite:

2013-07-29  Bill Schmidt  <wschmidt@vnet.linux.ibm.com>

	PR tree-optimization/57993
	* gcc.dg/torture/pr57993.c: New test.

From-SVN: r201325

gcc/ChangeLog

+2013-07-29  Bill Schmidt  <wschmidt@vnet.linux.ibm.com>
+
+	PR tree-optimization/57993
+	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Record
+	replaced statement in the candidate table.
+	(phi_add_costs): Return infinite cost when the hidden basis does
+	not dominate all phis on which the candidate is dependent.
+	(replace_one_candidate): Record replaced statement in the
+	candidate table.
+
 2013-07-29  Joern Rennecke  <joern.rennecke@embecosm.com>
 
 	* config/epiphany/epiphany.md (*isub_i+2): New peephole.

gcc/gimple-ssa-strength-reduction.c

@@ -1882,6 +1882,7 @@ replace_mult_candidate (slsr_cand_t c, tree basis_name, double_int bump)
 	  gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
 	  gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
 	  gsi_replace (&gsi, copy_stmt, false);
+	  c->cand_stmt = copy_stmt;
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    stmt_to_print = copy_stmt;
 	}
@@ -2179,6 +2180,18 @@ phi_add_costs (gimple phi, slsr_cand_t c, int one_add_cost)
   int cost = 0;
   slsr_cand_t phi_cand = base_cand_from_table (gimple_phi_result (phi));
 
+  /* If we work our way back to a phi that isn't dominated by the hidden
+     basis, this isn't a candidate for replacement.  Indicate this by
+     returning an unreasonably high cost.  It's not easy to detect
+     these situations when determining the basis, so we defer the
+     decision until now.  */
+  basic_block phi_bb = gimple_bb (phi);
+  slsr_cand_t basis = lookup_cand (c->basis);
+  basic_block basis_bb = gimple_bb (basis->cand_stmt);
+
+  if (phi_bb == basis_bb || !dominated_by_p (CDI_DOMINATORS, phi_bb, basis_bb))
+    return COST_INFINITE;
+
   for (i = 0; i < gimple_phi_num_args (phi); i++)
     {
       tree arg = gimple_phi_arg_def (phi, i);
@@ -3226,6 +3239,7 @@ replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name)
 	  gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
 	  gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
 	  gsi_replace (&gsi, copy_stmt, false);
+	  c->cand_stmt = copy_stmt;
 
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    stmt_to_print = copy_stmt;
@@ -3238,6 +3252,7 @@ replace_one_candidate (slsr_cand_t c, unsigned i, tree basis_name)
 							   NULL_TREE);
 	  gimple_set_location (cast_stmt, gimple_location (c->cand_stmt));
 	  gsi_replace (&gsi, cast_stmt, false);
+	  c->cand_stmt = cast_stmt;
 
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    stmt_to_print = cast_stmt;

gcc/testsuite/ChangeLog

+2013-07-29  Bill Schmidt  <wschmidt@vnet.linux.ibm.com>
+
+	PR tree-optimization/57993
+	* gcc.dg/torture/pr57993.c: New test.
+
 2013-07-29  Joern Rennecke  <joern.rennecke@embecosm.com>
 
 	* gcc.dg/tree-ssa/pr44258.c: Disable scan test for Epiphany.

gcc/testsuite/gcc.dg/torture/pr57993.c

+/* This ICEd prior to fixing PR57993.  */
+/* { dg-do compile } */
+
+int a, b, c, d;
+char e;
+unsigned g;
+
+void f(void)
+{
+    int h;
+
+    for(; d; d++)
+        if(d)
+lbl:
+            g + a || (d = 0);
+
+    b && (a = e);
+
+    for(h = 0; h < 1; ++h)
+    {
+        h = c ? : (d = 0);
+        g = a = (e | 0);
+    }
+
+    if(a)
+        goto lbl;
+
+    a = e = 0;
+    goto lbl;
+}