Revert "c++: Fix up cp_build_array_ref COND_EXPR handling [PR120471]"

This reverts commit b5f0faa4eb71650a9dde3938c3a98eda710534de.

3 files changed, 7 insertions, 186 deletions

diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 19dfaf18928..89ff595ec51 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -3811,129 +3811,13 @@ cp_build_array_ref (location_t loc, tree array, tree idx,
       }
 
     case COND_EXPR:
-      tree op0, op1, op2;
-      op0 = TREE_OPERAND (array, 0);
-      op1 = TREE_OPERAND (array, 1);
-      op2 = TREE_OPERAND (array, 1);
-      if (TREE_SIDE_EFFECTS (idx) || !tree_invariant_p (idx))
-	{
-	  /* If idx could possibly have some SAVE_EXPRs, turning
-	     (op0 ? op1 : op2)[idx] into
-	     op0 ? op1[idx] : op2[idx] can lead into temporaries
-	     initialized in one conditional path and uninitialized
-	     uses of them in the other path.
-	     And if idx is a really large expression, evaluating it
-	     twice is also not optimal.
-	     On the other side, op0 must be sequenced before evaluation
-	     of op1 and op2 and for C++17 op0, op1 and op2 must be
-	     sequenced before idx.
-	     If idx is INTEGER_CST, we can just do the optimization
-	     without any SAVE_EXPRs, if op1 and op2 are both ARRAY_TYPE
-	     VAR_DECLs or COMPONENT_REFs thereof (so their address
-	     is constant or relative to frame), optimize into
-	     (SAVE_EXPR <op0>, SAVE_EXPR <idx>, SAVE_EXPR <op0>)
-	     ? op1[SAVE_EXPR <idx>] : op2[SAVE_EXPR <idx>]
-	     Otherwise avoid this optimization.  */
-	  if (flag_strong_eval_order == 2)
-	    {
-	      if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
-		{
-		  tree xop1 = op1;
-		  tree xop2 = op2;
-		  while (xop1 && handled_component_p (xop1))
-		    {
-		      switch (TREE_CODE (xop1))
-			{
-			case ARRAY_REF:
-			case ARRAY_RANGE_REF:
-			  if (!tree_invariant_p (TREE_OPERAND (xop1, 1))
-			      || TREE_OPERAND (xop1, 2) != NULL_TREE
-			      || TREE_OPERAND (xop1, 3) != NULL_TREE)
-			    {
-			      xop1 = NULL_TREE;
-			      continue;
-			    }
-			  break;
-
-			case COMPONENT_REF:
-			  if (TREE_OPERAND (xop1, 2) != NULL_TREE)
-			    {
-			      xop1 = NULL_TREE;
-			      continue;
-			    }
-			  break;
-
-			default:
-			  break;
-			}
-		      xop1 = TREE_OPERAND (xop1, 0);
-		    }
-		  if (xop1)
-		    STRIP_ANY_LOCATION_WRAPPER (xop1);
-		  while (xop2 && handled_component_p (xop2))
-		    {
-		      switch (TREE_CODE (xop2))
-			{
-			case ARRAY_REF:
-			case ARRAY_RANGE_REF:
-			  if (!tree_invariant_p (TREE_OPERAND (xop2, 1))
-			      || TREE_OPERAND (xop2, 2) != NULL_TREE
-			      || TREE_OPERAND (xop2, 3) != NULL_TREE)
-			    {
-			      xop2 = NULL_TREE;
-			      continue;
-			    }
-			  break;
-
-			case COMPONENT_REF:
-			  if (TREE_OPERAND (xop2, 2) != NULL_TREE)
-			    {
-			      xop2 = NULL_TREE;
-			      continue;
-			    }
-			  break;
-
-			default:
-			  break;
-			}
-		      xop2 = TREE_OPERAND (xop2, 0);
-		    }
-		  if (xop2)
-		    STRIP_ANY_LOCATION_WRAPPER (xop2);
-
-		  if (!xop1
-		      || !xop2
-		      || !(CONSTANT_CLASS_P (xop1)
-			   || decl_address_invariant_p (xop1))
-		      || !(CONSTANT_CLASS_P (xop2)
-			   || decl_address_invariant_p (xop2)))
-		    {
-		      /* Force default conversion on array if
-			 we can't optimize this and array is ARRAY_TYPE
-			 COND_EXPR, we can't leave COND_EXPRs with
-			 ARRAY_TYPE in the IL.  */
-		      array = cp_default_conversion (array, complain);
-		      if (error_operand_p (array))
-			return error_mark_node;
-		      break;
-		    }
-		}
-	      else if (!POINTER_TYPE_P (TREE_TYPE (array))
-		       || !tree_invariant_p (op1)
-		       || !tree_invariant_p (op2))
-		break;
-	    }
-	  if (TREE_SIDE_EFFECTS (idx))
-	    {
-	      idx = save_expr (idx);
-	      op0 = save_expr (op0);
-	      tree tem = build_compound_expr (loc, op0, idx);
-	      op0 = build_compound_expr (loc, tem, op0);
-	    }
-	}
-      op1 = cp_build_array_ref (loc, op1, idx, complain);
-      op2 = cp_build_array_ref (loc, op2, idx, complain);
-      ret = build_conditional_expr (loc, op0, op1, op2, complain);
+      ret = build_conditional_expr
+	       (loc, TREE_OPERAND (array, 0),
+	       cp_build_array_ref (loc, TREE_OPERAND (array, 1), idx,
+				   complain),
+	       cp_build_array_ref (loc, TREE_OPERAND (array, 2), idx,
+				   complain),
+	       complain);
       protected_set_expr_location (ret, loc);
       return ret;
 
diff --git a/gcc/testsuite/g++.dg/parse/pr120471.C b/gcc/testsuite/g++.dg/parse/pr120471.C
deleted file mode 100644
index ad47e380404..00000000000
--- a/gcc/testsuite/g++.dg/parse/pr120471.C
+++ /dev/null
@@ -1,42 +0,0 @@
-// PR c++/120471
-// { dg-do compile }
-
-extern int a1[], a2[], a3[], a4[];
-
-int corge (int);
-
-int
-foo (int p)
-{
-  return (p ? a1 : a2)[1];
-}
-
-int
-bar (int p, int q)
-{
-  return (p ? a1 : a2)[q];
-}
-
-int
-garply (int p, int q)
-{
-  return (p ? a1 : a2)[corge (q)];
-}
-
-int
-baz (int p, int q)
-{
-  return (p ? q ? a1 : a2 : q ? a3 : a4)[1];
-}
-
-int
-qux (int p, int q, int r)
-{
-  return (p ? q ? a1 : a2 : q ? a3 : a4)[r];
-}
-
-int
-fred (int p, int q, int r)
-{
-  return (p ? q ? a1 : a2 : q ? a3 : a4)[corge (r)];
-}
diff --git a/gcc/testsuite/g++.dg/ubsan/pr120471.C b/gcc/testsuite/g++.dg/ubsan/pr120471.C
deleted file mode 100644
index 31b781f9aa7..00000000000
--- a/gcc/testsuite/g++.dg/ubsan/pr120471.C
+++ /dev/null
@@ -1,21 +0,0 @@
-// PR c++/120471
-// { dg-do run }
-// { dg-options "-fsanitize=undefined" }
-
-volatile int b[1], a[1];
-
-void
-foo (int x)
-{
-  volatile int c = 21;
-  volatile int v = (x % 2 ? b : a)[c % 3];
-  if (v != 0)
-    __builtin_abort ();
-}
-
-int
-main ()
-{
-  foo (1);
-  foo (2);
-}