From c89529306c91eafa81c762e9050d51c747c14af0 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Wed, 7 Dec 2016 20:45:45 +0100 Subject: [PATCH] builtins.c (fold_builtin_strstr): Removed. * builtins.c (fold_builtin_strstr): Removed. (fold_builtin_2): Don't call fold_builtin_strstr. * gimple-fold.c (gimple_fold_builtin_strchr): Check is_strrchr earlier in the strrchr (x, 0) -> strchr (x, 0) optimization. (gimple_fold_builtin_strstr): New function. (gimple_fold_builtin): Call it. * fold-const-call.c (fold_const_call): Handle CFN_BUILT_IN_STRSTR. * gcc.dg/builtin-strstr-1.c: New test. * g++.dg/cpp0x/constexpr-strstr.C: New test. From-SVN: r243378 --- gcc/ChangeLog | 8 +++ gcc/builtins.c | 70 --------------------------- gcc/fold-const-call.c | 16 ++++++ gcc/gimple-fold.c | 68 +++++++++++++++++++++++++- gcc/testsuite/ChangeLog | 3 ++ gcc/testsuite/g++.dg/cpp0x/constexpr-strstr.C | 12 +++++ gcc/testsuite/gcc.dg/builtin-strstr-1.c | 31 ++++++++++++ 7 files changed, 136 insertions(+), 72 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-strstr.C create mode 100644 gcc/testsuite/gcc.dg/builtin-strstr-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b14b790..cc6dc71 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,13 @@ 2016-12-07 Jakub Jelinek + * builtins.c (fold_builtin_strstr): Removed. + (fold_builtin_2): Don't call fold_builtin_strstr. + * gimple-fold.c (gimple_fold_builtin_strchr): Check is_strrchr + earlier in the strrchr (x, 0) -> strchr (x, 0) optimization. + (gimple_fold_builtin_strstr): New function. + (gimple_fold_builtin): Call it. + * fold-const-call.c (fold_const_call): Handle CFN_BUILT_IN_STRSTR. + PR c++/78692 * cgraph.c (cgraph_edge::redirect_call_stmt_to_callee): Set lhs var to lhs of new_stmt right before noreturn handling rather than to diff --git a/gcc/builtins.c b/gcc/builtins.c index 1316c27..58ed469 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -163,7 +163,6 @@ static tree fold_builtin_3 (location_t, tree, tree, tree, tree); static tree fold_builtin_varargs (location_t, tree, tree*, int); static tree fold_builtin_strpbrk (location_t, tree, tree, tree); -static tree fold_builtin_strstr (location_t, tree, tree, tree); static tree fold_builtin_strspn (location_t, tree, tree); static tree fold_builtin_strcspn (location_t, tree, tree); @@ -8303,9 +8302,6 @@ fold_builtin_2 (location_t loc, tree fndecl, tree arg0, tree arg1) CASE_FLT_FN (BUILT_IN_MODF): return fold_builtin_modf (loc, arg0, arg1, type); - case BUILT_IN_STRSTR: - return fold_builtin_strstr (loc, arg0, arg1, type); - case BUILT_IN_STRSPN: return fold_builtin_strspn (loc, arg0, arg1); @@ -8729,72 +8725,6 @@ readonly_data_expr (tree exp) return false; } -/* Simplify a call to the strstr builtin. S1 and S2 are the arguments - to the call, and TYPE is its return type. - - Return NULL_TREE if no simplification was possible, otherwise return the - simplified form of the call as a tree. - - The simplified form may be a constant or other expression which - computes the same value, but in a more efficient manner (including - calls to other builtin functions). - - The call may contain arguments which need to be evaluated, but - which are not useful to determine the result of the call. In - this case we return a chain of COMPOUND_EXPRs. The LHS of each - COMPOUND_EXPR will be an argument which must be evaluated. - COMPOUND_EXPRs are chained through their RHS. The RHS of the last - COMPOUND_EXPR in the chain will contain the tree for the simplified - form of the builtin function call. */ - -static tree -fold_builtin_strstr (location_t loc, tree s1, tree s2, tree type) -{ - if (!validate_arg (s1, POINTER_TYPE) - || !validate_arg (s2, POINTER_TYPE)) - return NULL_TREE; - else - { - tree fn; - const char *p1, *p2; - - p2 = c_getstr (s2); - if (p2 == NULL) - return NULL_TREE; - - p1 = c_getstr (s1); - if (p1 != NULL) - { - const char *r = strstr (p1, p2); - tree tem; - - if (r == NULL) - return build_int_cst (TREE_TYPE (s1), 0); - - /* Return an offset into the constant string argument. */ - tem = fold_build_pointer_plus_hwi_loc (loc, s1, r - p1); - return fold_convert_loc (loc, type, tem); - } - - /* The argument is const char *, and the result is char *, so we need - a type conversion here to avoid a warning. */ - if (p2[0] == '\0') - return fold_convert_loc (loc, type, s1); - - if (p2[1] != '\0') - return NULL_TREE; - - fn = builtin_decl_implicit (BUILT_IN_STRCHR); - if (!fn) - return NULL_TREE; - - /* New argument list transforming strstr(s1, s2) to - strchr(s1, s2[0]). */ - return build_call_expr_loc (loc, fn, 2, s1, - build_int_cst (integer_type_node, p2[0])); - } -} - /* Simplify a call to the strpbrk builtin. S1 and S2 are the arguments to the call, and TYPE is its return type. diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c index c85fb41..f978da3 100644 --- a/gcc/fold-const-call.c +++ b/gcc/fold-const-call.c @@ -1434,6 +1434,22 @@ fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1) } return NULL_TREE; + case CFN_BUILT_IN_STRSTR: + if ((p1 = c_getstr (arg1))) + { + if ((p0 = c_getstr (arg0))) + { + const char *r = strstr (p0, p1); + if (r == NULL) + return build_int_cst (type, 0); + return fold_convert (type, + fold_build_pointer_plus_hwi (arg0, r - p0)); + } + if (*p1 == '\0') + return fold_convert (type, arg0); + } + return NULL_TREE; + default: return fold_const_call_1 (fn, type, arg0, arg1); } diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c index f586c09..d00625b 100644 --- a/gcc/gimple-fold.c +++ b/gcc/gimple-fold.c @@ -1506,11 +1506,11 @@ gimple_fold_builtin_strchr (gimple_stmt_iterator *gsi, bool is_strrchr) return false; /* Transform strrchr (s, 0) to strchr (s, 0) when optimizing for size. */ - if (optimize_function_for_size_p (cfun)) + if (is_strrchr && optimize_function_for_size_p (cfun)) { tree strchr_fn = builtin_decl_implicit (BUILT_IN_STRCHR); - if (is_strrchr && strchr_fn) + if (strchr_fn) { gimple *repl = gimple_build_call (strchr_fn, 2, str, c); replace_call_with_call_and_fold (gsi, repl); @@ -1549,6 +1549,68 @@ gimple_fold_builtin_strchr (gimple_stmt_iterator *gsi, bool is_strrchr) return true; } +/* Fold function call to builtin strstr. + If both arguments are constant, evaluate and fold the result, + additionally fold strstr (x, "") into x and strstr (x, "c") + into strchr (x, 'c'). */ +static bool +gimple_fold_builtin_strstr (gimple_stmt_iterator *gsi) +{ + gimple *stmt = gsi_stmt (*gsi); + tree haystack = gimple_call_arg (stmt, 0); + tree needle = gimple_call_arg (stmt, 1); + const char *p, *q; + + if (!gimple_call_lhs (stmt)) + return false; + + q = c_getstr (needle); + if (q == NULL) + return false; + + if ((p = c_getstr (haystack))) + { + const char *r = strstr (p, q); + + if (r == NULL) + { + replace_call_with_value (gsi, integer_zero_node); + return true; + } + + tree len = build_int_cst (size_type_node, r - p); + gimple_seq stmts = NULL; + gimple *new_stmt + = gimple_build_assign (gimple_call_lhs (stmt), POINTER_PLUS_EXPR, + haystack, len); + gimple_seq_add_stmt_without_update (&stmts, new_stmt); + gsi_replace_with_seq_vops (gsi, stmts); + return true; + } + + /* For strstr (x, "") return x. */ + if (q[0] == '\0') + { + replace_call_with_value (gsi, haystack); + return true; + } + + /* Transform strstr (x, "c") into strchr (x, 'c'). */ + if (q[1] == '\0') + { + tree strchr_fn = builtin_decl_implicit (BUILT_IN_STRCHR); + if (strchr_fn) + { + tree c = build_int_cst (integer_type_node, q[0]); + gimple *repl = gimple_build_call (strchr_fn, 2, haystack, c); + replace_call_with_call_and_fold (gsi, repl); + return true; + } + } + + return false; +} + /* Simplify a call to the strcat builtin. DST and SRC are the arguments to the call. @@ -3236,6 +3298,8 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi) case BUILT_IN_RINDEX: case BUILT_IN_STRRCHR: return gimple_fold_builtin_strchr (gsi, true); + case BUILT_IN_STRSTR: + return gimple_fold_builtin_strstr (gsi); case BUILT_IN_STRCMP: case BUILT_IN_STRCASECMP: case BUILT_IN_STRNCMP: diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2706d0e..1c3f290 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2016-12-07 Jakub Jelinek + * gcc.dg/builtin-strstr-1.c: New test. + * g++.dg/cpp0x/constexpr-strstr.C: New test. + PR c++/78692 * g++.dg/torture/pr78692.C: New test. diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-strstr.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-strstr.C new file mode 100644 index 0000000..4268909 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-strstr.C @@ -0,0 +1,12 @@ +// { dg-do compile { target c++11 } } + +constexpr const char *f1 (const char *p, const char *q) { return __builtin_strstr (p, q); } +constexpr const char a[] = "abcdefedcbaaaaab"; +constexpr const char b[] = "fed"; +constexpr const char c[] = "aaab"; +static_assert (f1 ("abcde", "ee") == nullptr, ""); +static_assert (f1 (a, b) == a + 5, ""); +static_assert (f1 (a, c) == a + 12, ""); +static_assert (f1 (a, "") == a, ""); +static_assert (f1 (a, "aaaaaab") == nullptr, ""); +static_assert (f1 (a, "aaa") == a + 10, ""); diff --git a/gcc/testsuite/gcc.dg/builtin-strstr-1.c b/gcc/testsuite/gcc.dg/builtin-strstr-1.c new file mode 100644 index 0000000..9d584b6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/builtin-strstr-1.c @@ -0,0 +1,31 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +/* { dg-final { scan-tree-dump-not "link_error" "optimized" } } */ +/* { dg-final { scan-tree-dump-not "__builtin_strstr" "optimized" } } */ +/* { dg-final { scan-tree-dump-times "return p_\[0-9]*.D.;" 1 "optimized" } } */ +/* { dg-final { scan-tree-dump-times "__builtin_strchr" 1 "optimized" } } */ + +extern void link_error (void); + +void +foo (void) +{ + const char *p = "abcdef"; + const char *q = "def"; + p++; + q++; + if (__builtin_strstr (p, q) != p + 3) + link_error (); +} + +char * +bar (const char *p) +{ + return __builtin_strstr (p, ""); +} + +char * +baz (const char *p) +{ + return __builtin_strstr (p, "d"); +} -- 2.7.4