re PR tree-optimization/80275 (Poor (but valid) code generated by optimizer…

re PR tree-optimization/80275 (Poor (but valid) code generated by optimizer passing optimizer list to function)

2017-04-03  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80275
	* fold-const.c (split_address_to_core_and_offset): Handle
	POINTER_PLUS_EXPR.

	* g++.dg/opt/pr80275.C: New testcase.

From-SVN: r246648

gcc/ChangeLog

+2017-04-03  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80275
+	* fold-const.c (split_address_to_core_and_offset): Handle
+	POINTER_PLUS_EXPR.
+
 2017-04-03  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* tree-nested.c (get_descriptor_type): Make sure that the alignment of

gcc/fold-const.c

@@ -14341,6 +14341,24 @@ split_address_to_core_and_offset (tree exp,
 				  &volatilep);
       core = build_fold_addr_expr_loc (loc, core);
     }
+  else if (TREE_CODE (exp) == POINTER_PLUS_EXPR)
+    {
+      core = TREE_OPERAND (exp, 0);
+      STRIP_NOPS (core);
+      *pbitpos = 0;
+      *poffset = TREE_OPERAND (exp, 1);
+      if (TREE_CODE (*poffset) == INTEGER_CST)
+	{
+	  offset_int tem = wi::sext (wi::to_offset (*poffset),
+				     TYPE_PRECISION (TREE_TYPE (*poffset)));
+	  tem <<= LOG2_BITS_PER_UNIT;
+	  if (wi::fits_shwi_p (tem))
+	    {
+	      *pbitpos = tem.to_shwi ();
+	      *poffset = NULL_TREE;
+	    }
+	}
+    }
   else
     {
       core = exp;

gcc/testsuite/ChangeLog

+2017-04-03  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80275
+	* g++.dg/opt/pr80275.C: New testcase.
+
 2017-04-03  Dominik Vogt  <vogt@linux.vnet.ibm.com>
 
 	PR testsuite/79356

gcc/testsuite/g++.dg/opt/pr80275.C

+// { dg-do compile { target c++14 } }
+// { dg-options "-O2 -fdump-tree-optimized" }
+
+#include <algorithm>
+
+int g()
+{
+      return 1234;
+}
+
+int f2()
+{
+      return std::min({1, g(), 4});
+}
+
+// { dg-final { scan-tree-dump "return 1;" "optimized" } }