re PR tree-optimization/79201 (missed optimization: sinking doesn't handle…

re PR tree-optimization/79201 (missed optimization: sinking doesn't handle calls, swap PRE and sinking)

2017-04-25  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79201
	* tree-ssa-sink.c (statement_sink_location): Handle calls.

	* gcc.dg/tree-ssa/ssa-sink-16.c: New testcase.
	* gcc.target/i386/pr22152.c: Disable sinking.

From-SVN: r247159

gcc/ChangeLog

+2017-04-25  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79201
+	* tree-ssa-sink.c (statement_sink_location): Handle calls.
+
 2017-04-25  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	PR target/80464

gcc/testsuite/ChangeLog

+2017-04-25  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79201
+	* gcc.dg/tree-ssa/ssa-sink-16.c: New testcase.
+	* gcc.target/i386/pr22152.c: Disable sinking.
+
 2017-04-25  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	PR target/80464

gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-16.c

+/* { dg-do compile } */
+/* Note PRE rotates the loop and blocks the sinking opportunity.  */
+/* { dg-options "-O2 -fno-tree-pre -fdump-tree-sink -fdump-tree-optimized" } */
+
+int f(int n)
+{
+  int i,j=0;
+  for (i = 0; i < 31; i++)
+    j = __builtin_ffs(i);
+  return j;
+}
+
+/* { dg-final { scan-tree-dump "Sinking j_. = __builtin_ffs" "sink" } } */
+/* { dg-final { scan-tree-dump "return 2;" "optimized" } } */

gcc/testsuite/gcc.target/i386/pr22152.c

 /* { dg-do compile } */
-/* { dg-options "-O2 -msse2 -mtune=core2" } */
+/* { dg-options "-O2 -fno-tree-sink -msse2 -mtune=core2" } */
 /* { dg-additional-options "-mno-vect8-ret-in-mem" { target *-*-vxworks* } } */
 /* { dg-additional-options "-mabi=sysv" { target x86_64-*-mingw* } } */
 

gcc/tree-ssa-sink.c

@@ -256,8 +256,12 @@ statement_sink_location (gimple *stmt, basic_block frombb,
 
   *zero_uses_p = false;
 
-  /* We only can sink assignments.  */
-  if (!is_gimple_assign (stmt))
+  /* We only can sink assignments and non-looping const/pure calls.  */
+  int cf;
+  if (!is_gimple_assign (stmt)
+      && (!is_gimple_call (stmt)
+	  || !((cf = gimple_call_flags (stmt)) & (ECF_CONST|ECF_PURE))
+	  || (cf & ECF_LOOPING_CONST_OR_PURE)))
     return false;
 
   /* We only can sink stmts with a single definition.  */
@@ -291,7 +295,7 @@ statement_sink_location (gimple *stmt, basic_block frombb,
   if (stmt_ends_bb_p (stmt)
       || gimple_has_side_effects (stmt)
       || (cfun->has_local_explicit_reg_vars
-	  && TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))) == BLKmode))
+	  && TYPE_MODE (TREE_TYPE (gimple_get_lhs (stmt))) == BLKmode))
     return false;
 
   /* Return if there are no immediate uses of this stmt.  */
@@ -323,15 +327,15 @@ statement_sink_location (gimple *stmt, basic_block frombb,
 
 	  /* A killing definition is not a use.  */
 	  if ((gimple_has_lhs (use_stmt)
-	       && operand_equal_p (gimple_assign_lhs (stmt),
+	       && operand_equal_p (gimple_get_lhs (stmt),
 				   gimple_get_lhs (use_stmt), 0))
-	      || stmt_kills_ref_p (use_stmt, gimple_assign_lhs (stmt)))
+	      || stmt_kills_ref_p (use_stmt, gimple_get_lhs (stmt)))
 	    {
 	      /* If use_stmt is or might be a nop assignment then USE_STMT
 	         acts as a use as well as definition.  */
 	      if (stmt != use_stmt
 		  && ref_maybe_used_by_stmt_p (use_stmt,
-					       gimple_assign_lhs (stmt)))
+					       gimple_get_lhs (stmt)))
 		return false;
 	      continue;
 	    }