https://gcc.gnu.org/g:486c32501aafce188649da2c234229dfbd2fd202
commit r12-11255-g486c32501aafce188649da2c234229dfbd2fd202
Author: Jakub Jelinek <ja...@redhat.com>
Date: Mon Jul 7 09:51:51 2025 +0200
Revert "c++: Fix up cp_build_array_ref COND_EXPR handling [PR120471]"
This reverts commit b5f0faa4eb71650a9dde3938c3a98eda710534de.
Diff:
---
gcc/cp/typeck.cc | 130 ++--------------------------------
gcc/testsuite/g++.dg/parse/pr120471.C | 42 -----------
gcc/testsuite/g++.dg/ubsan/pr120471.C | 21 ------
3 files changed, 7 insertions(+), 186 deletions(-)
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 19dfaf18928f..89ff595ec513 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 ad47e380404a..000000000000
--- 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 31b781f9aa7f..000000000000
--- 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);
-}
