From f594abf4b9ebf0976c6dbebc9abd51e0abd2da48 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Fri, 20 Mar 2015 21:53:40 +0000 Subject: [PATCH] re PR c++/65398 ([C++11] GCC rejects constexpr variable definitions with valid initialization) PR c++/65398 * constexpr.c (cxx_fold_indirect_ref): Transform *(&A[i] p+ j) into A[i + j]. * g++.dg/cpp0x/pr65398.C: New test. From-SVN: r221544 --- gcc/cp/ChangeLog | 6 +++ gcc/cp/constexpr.c | 21 +++++++++ gcc/testsuite/ChangeLog | 5 ++ gcc/testsuite/g++.dg/cpp0x/pr65398.C | 70 ++++++++++++++++++++++++++++ 4 files changed, 102 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr65398.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index dadf6739ad1..9bc6337991b 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2015-03-20 Marek Polacek + + PR c++/65398 + * constexpr.c (cxx_fold_indirect_ref): Transform *(&A[i] p+ j) into + A[i + j]. + 2015-03-20 Marek Polacek PR c++/65072 diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 1b5f50cb494..37b619d56ff 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -2427,6 +2427,27 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) break; } } + /* *(&A[i] p+ j) => A[i + j] */ + else if (TREE_CODE (op00) == ARRAY_REF + && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST + && TREE_CODE (op01) == INTEGER_CST) + { + tree t = fold_convert_loc (loc, ssizetype, + TREE_OPERAND (op00, 1)); + tree nelts + = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); + /* Don't fold an out-of-bound access. */ + if (!tree_int_cst_le (t, nelts)) + return NULL_TREE; + /* Make sure to treat the second operand of POINTER_PLUS_EXPR + as signed. */ + op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, + cp_fold_convert (ssizetype, op01), + TYPE_SIZE_UNIT (type)); + t = size_binop_loc (loc, PLUS_EXPR, op01, t); + return build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), + t, NULL_TREE, NULL_TREE); + } } } /* *(foo *)fooarrptr => (*fooarrptr)[0] */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 8f6bde77004..a62b54c58a6 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2015-03-20 Marek Polacek + + PR c++/65398 + * g++.dg/cpp0x/pr65398.C: New test. + 2015-03-20 Jan Hubicka PR ipa/65475 diff --git a/gcc/testsuite/g++.dg/cpp0x/pr65398.C b/gcc/testsuite/g++.dg/cpp0x/pr65398.C new file mode 100644 index 00000000000..a4aeba580fc --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/pr65398.C @@ -0,0 +1,70 @@ +// PR c++/65398 +// { dg-do compile { target c++11 } } + +#define SA(X) static_assert((X),#X) + +constexpr char s[] = "abc"; +constexpr char c1 = *(&s[0] + 0); +constexpr char c2 = *(&s[0] + 1); +constexpr char c3 = *(&s[1] + 0); +constexpr char c4 = *(&s[1] + 1); +constexpr char c5 = *(&s[2] + 0); +constexpr char c6 = *(&s[0] + 2); +constexpr char c7 = *(&s[2] + 1); + +constexpr char d1 = *(&s[4] - 0); // { dg-error "array subscript out of bound" } +constexpr char d2 = *(&s[4] - 1); +constexpr char d3 = *(&s[4] - 2); +constexpr char d4 = *(&s[4] - 3); +constexpr char d5 = *(&s[4] - 4); +constexpr char d6 = *(&s[4] - 5); // { dg-error "negative array subscript" } + +/* Don't accept invalid stuff. */ +constexpr char e1 = *(&s[5] - 1); // { dg-error "is not a constant expression" } +constexpr char e2 = *(&s[5] - 2); // { dg-error "is not a constant expression" } +constexpr char e3 = *(&s[5] - 3); // { dg-error "is not a constant expression" } + +SA (c1 == 'a'); +SA (c2 == 'b'); +SA (c3 == 'b'); +SA (c4 == 'c'); +SA (c5 == 'c'); +SA (c6 == 'c'); +SA (c7 == '\0'); +SA (d2 == '\0'); +SA (d3 == 'c'); +SA (d4 == 'b'); +SA (d5 == 'a'); + +constexpr int l[] = { 'c', 'd', 'e', '\0' }; +constexpr int i1 = *(&l[0] + 0); +constexpr int i2 = *(&l[0] + 1); +constexpr int i3 = *(&l[1] + 0); +constexpr int i4 = *(&l[1] + 1); +constexpr int i5 = *(&l[2] + 0); +constexpr int i6 = *(&l[0] + 2); +constexpr int i7 = *(&l[2] + 1); + +constexpr char j1 = *(&l[4] - 0); // { dg-error "array subscript out of bound" } +constexpr char j2 = *(&l[4] - 1); +constexpr char j3 = *(&l[4] - 2); +constexpr char j4 = *(&l[4] - 3); +constexpr char j5 = *(&l[4] - 4); +constexpr char j6 = *(&l[4] - 5); // { dg-error "negative array subscript" } + +/* Don't accept invalid stuff. */ +constexpr char k1 = *(&l[5] - 1); // { dg-error "is not a constant expression" } +constexpr char k2 = *(&l[5] - 2); // { dg-error "is not a constant expression" } +constexpr char k3 = *(&l[5] - 3); // { dg-error "is not a constant expression" } + +SA (i1 == 'c'); +SA (i2 == 'd'); +SA (i3 == 'd'); +SA (i4 == 'e'); +SA (i5 == 'e'); +SA (i6 == 'e'); +SA (i7 == '\0'); +SA (j2 == '\0'); +SA (j3 == 'e'); +SA (j4 == 'd'); +SA (j5 == 'c'); -- 2.30.2