re PR tree-optimization/81503 (Wrong code at -O2)

[gcc]

2017-08-29  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
	    Jakub Jelinek  <jakub@redhat.com>
	    Richard Biener  <rguenther@suse.de>

	PR tree-optimization/81503
	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Ensure
	folded constant fits in the target type; reorder tests for clarity.

[gcc/testsuite]

2017-08-29  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/81503
	* gcc.c-torture/execute/pr81503.c: New file.


Co-Authored-By: Jakub Jelinek <jakub@redhat.com>
Co-Authored-By: Richard Biener <rguenther@suse.de>

From-SVN: r251414

gcc/ChangeLog

+2017-08-29  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+	    Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/81503
+	* gimple-ssa-strength-reduction.c (replace_mult_candidate): Ensure
+	folded constant fits in the target type; reorder tests for clarity.
+
 2017-08-29  Martin Liska  <mliska@suse.cz>
 
 	* passes.def: Include pass_lower_switch.

gcc/gimple-ssa-strength-reduction.c

@@ -2089,104 +2089,104 @@ replace_mult_candidate (slsr_cand_t c, tree basis_name, widest_int bump)
   tree target_type = TREE_TYPE (gimple_assign_lhs (c->cand_stmt));
   enum tree_code cand_code = gimple_assign_rhs_code (c->cand_stmt);
 
-  /* It is highly unlikely, but possible, that the resulting
-     bump doesn't fit in a HWI.  Abandon the replacement
-     in this case.  This does not affect siblings or dependents
-     of C.  Restriction to signed HWI is conservative for unsigned
-     types but allows for safe negation without twisted logic.  */
-  if (wi::fits_shwi_p (bump)
-      && bump.to_shwi () != HOST_WIDE_INT_MIN
-      /* It is not useful to replace casts, copies, negates, or adds of
-	 an SSA name and a constant.  */
-      && cand_code != SSA_NAME
-      && !CONVERT_EXPR_CODE_P (cand_code)
-      && cand_code != PLUS_EXPR
-      && cand_code != POINTER_PLUS_EXPR
-      && cand_code != MINUS_EXPR
-      && cand_code != NEGATE_EXPR)
-    {
-      enum tree_code code = PLUS_EXPR;
-      tree bump_tree;
-      gimple *stmt_to_print = NULL;
+  /* It is not useful to replace casts, copies, negates, or adds of
+     an SSA name and a constant.  */
+  if (cand_code == SSA_NAME
+      || CONVERT_EXPR_CODE_P (cand_code)
+      || cand_code == PLUS_EXPR
+      || cand_code == POINTER_PLUS_EXPR
+      || cand_code == MINUS_EXPR
+      || cand_code == NEGATE_EXPR)
+    return;
 
-      /* If the basis name and the candidate's LHS have incompatible
-	 types, introduce a cast.  */
-      if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name)))
-	basis_name = introduce_cast_before_cand (c, target_type, basis_name);
-      if (wi::neg_p (bump))
-	{
-	  code = MINUS_EXPR;
-	  bump = -bump;
-	}
+  enum tree_code code = PLUS_EXPR;
+  tree bump_tree;
+  gimple *stmt_to_print = NULL;
 
-      bump_tree = wide_int_to_tree (target_type, bump);
+  if (wi::neg_p (bump))
+    {
+      code = MINUS_EXPR;
+      bump = -bump;
+    }
+
+  /* It is possible that the resulting bump doesn't fit in target_type.
+     Abandon the replacement in this case.  This does not affect
+     siblings or dependents of C.  */
+  if (bump != wi::ext (bump, TYPE_PRECISION (target_type),
+		       TYPE_SIGN (target_type)))
+    return;
+
+  bump_tree = wide_int_to_tree (target_type, bump);
+
+  /* If the basis name and the candidate's LHS have incompatible types,
+     introduce a cast.  */
+  if (!useless_type_conversion_p (target_type, TREE_TYPE (basis_name)))
+    basis_name = introduce_cast_before_cand (c, target_type, basis_name);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fputs ("Replacing: ", dump_file);
+      print_gimple_stmt (dump_file, c->cand_stmt, 0);
+    }
 
+  if (bump == 0)
+    {
+      tree lhs = gimple_assign_lhs (c->cand_stmt);
+      gassign *copy_stmt = gimple_build_assign (lhs, basis_name);
+      gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
+      slsr_cand_t cc = c;
+      gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
+      gsi_replace (&gsi, copy_stmt, false);
+      c->cand_stmt = copy_stmt;
+      while (cc->next_interp)
+	{
+	  cc = lookup_cand (cc->next_interp);
+	  cc->cand_stmt = copy_stmt;
+	}
       if (dump_file && (dump_flags & TDF_DETAILS))
+	stmt_to_print = copy_stmt;
+    }
+  else
+    {
+      tree rhs1, rhs2;
+      if (cand_code != NEGATE_EXPR) {
+	rhs1 = gimple_assign_rhs1 (c->cand_stmt);
+	rhs2 = gimple_assign_rhs2 (c->cand_stmt);
+      }
+      if (cand_code != NEGATE_EXPR
+	  && ((operand_equal_p (rhs1, basis_name, 0)
+	       && operand_equal_p (rhs2, bump_tree, 0))
+	      || (operand_equal_p (rhs1, bump_tree, 0)
+		  && operand_equal_p (rhs2, basis_name, 0))))
 	{
-	  fputs ("Replacing: ", dump_file);
-	  print_gimple_stmt (dump_file, c->cand_stmt, 0);
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fputs ("(duplicate, not actually replacing)", dump_file);
+	      stmt_to_print = c->cand_stmt;
+	    }
 	}
-
-      if (bump == 0)
+      else
 	{
-	  tree lhs = gimple_assign_lhs (c->cand_stmt);
-	  gassign *copy_stmt = gimple_build_assign (lhs, basis_name);
 	  gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
 	  slsr_cand_t cc = c;
-	  gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
-	  gsi_replace (&gsi, copy_stmt, false);
-	  c->cand_stmt = copy_stmt;
+	  gimple_assign_set_rhs_with_ops (&gsi, code, basis_name, bump_tree);
+	  update_stmt (gsi_stmt (gsi));
+	  c->cand_stmt = gsi_stmt (gsi);
 	  while (cc->next_interp)
 	    {
 	      cc = lookup_cand (cc->next_interp);
-	      cc->cand_stmt = copy_stmt;
+	      cc->cand_stmt = gsi_stmt (gsi);
 	    }
 	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    stmt_to_print = copy_stmt;
-	}
-      else
-	{
-	  tree rhs1, rhs2;
-	  if (cand_code != NEGATE_EXPR) {
-	    rhs1 = gimple_assign_rhs1 (c->cand_stmt);
-	    rhs2 = gimple_assign_rhs2 (c->cand_stmt);
-	  }
-	  if (cand_code != NEGATE_EXPR
-	      && ((operand_equal_p (rhs1, basis_name, 0)
-		   && operand_equal_p (rhs2, bump_tree, 0))
-		  || (operand_equal_p (rhs1, bump_tree, 0)
-		      && operand_equal_p (rhs2, basis_name, 0))))
-	    {
-	      if (dump_file && (dump_flags & TDF_DETAILS))
-		{
-		  fputs ("(duplicate, not actually replacing)", dump_file);
-		  stmt_to_print = c->cand_stmt;
-		}
-	    }
-	  else
-	    {
-	      gimple_stmt_iterator gsi = gsi_for_stmt (c->cand_stmt);
-	      slsr_cand_t cc = c;
-	      gimple_assign_set_rhs_with_ops (&gsi, code,
-					      basis_name, bump_tree);
-	      update_stmt (gsi_stmt (gsi));
-              c->cand_stmt = gsi_stmt (gsi);
-	      while (cc->next_interp)
-		{
-		  cc = lookup_cand (cc->next_interp);
-		  cc->cand_stmt = gsi_stmt (gsi);
-		}
-	      if (dump_file && (dump_flags & TDF_DETAILS))
-		stmt_to_print = gsi_stmt (gsi);
-	    }
+	    stmt_to_print = gsi_stmt (gsi);
 	}
+    }
   
-      if (dump_file && (dump_flags & TDF_DETAILS))
-	{
-	  fputs ("With: ", dump_file);
-	  print_gimple_stmt (dump_file, stmt_to_print, 0);
-	  fputs ("\n", dump_file);
-  	}
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fputs ("With: ", dump_file);
+      print_gimple_stmt (dump_file, stmt_to_print, 0);
+      fputs ("\n", dump_file);
     }
 }
 

gcc/testsuite/ChangeLog

+2017-08-29  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/81503
+	* gcc.c-torture/execute/pr81503.c: New file.
+
 2017-08-29  Martin Liska  <mliska@suse.cz>
 
 	* gcc.dg/tree-prof/update-loopch.c: Scan patterns in

gcc/testsuite/gcc.c-torture/execute/pr81503.c

+unsigned short a = 41461;
+unsigned short b = 3419;
+int c = 0;
+
+void foo() {
+  if (a + b * ~(0 != 5))
+    c = -~(b * ~(0 != 5)) + 2147483647;
+}
+
+int main() {
+  foo();
+  if (c != 2147476810)
+    return -1;
+  return 0;
+}