From: Prathamesh Kulkarni Date: Wed, 14 Dec 2016 09:10:31 +0000 (+0000) Subject: tree-ssa-strlen.c (fold_strstr_to_memcmp): New function. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3b1970cb3c603c900a175d9c7c36428cc031920f;p=gcc.git tree-ssa-strlen.c (fold_strstr_to_memcmp): New function. 2016-12-14 Prathamesh Kulkarni Jakub Jelinek * tree-ssa-strlen.c (fold_strstr_to_memcmp): New function. (strlen_optimize_stmt): Call fold_strstr_to_memcmp. testsuite/ * gcc.dg/strlenopt-30.c: New test-case. Co-Authored-By: Jakub Jelinek From-SVN: r243633 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 24c6672e008..93235608438 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2016-12-14 Prathamesh Kulkarni + Jakub Jelinek + + * tree-ssa-strlen.c (fold_strstr_to_memcmp): New function. + (strlen_optimize_stmt): Call fold_strstr_to_memcmp. + 2016-12-14 Eric Botcazou * lra-constraints.c (process_address_1): Do not attempt to decompose diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 2be6da24268..d37ce76f905 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-12-14 Prathamesh Kulkarni + Jakub Jelinek + + * gcc.dg/strlenopt-30.c: New test-case. + 2016-12-14 Richard Biener PR tree-optimization/78788 diff --git a/gcc/testsuite/gcc.dg/strlenopt-30.c b/gcc/testsuite/gcc.dg/strlenopt-30.c new file mode 100644 index 00000000000..089b3a2341d --- /dev/null +++ b/gcc/testsuite/gcc.dg/strlenopt-30.c @@ -0,0 +1,63 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-strlen" } */ + +__attribute__((no_icf)) +_Bool f1(char *s) +{ + return __builtin_strstr (s, "hello") == s; +} + +__attribute__((no_icf)) +_Bool f2(char *s) +{ + return s == __builtin_strstr (s, "hello"); +} + +__attribute__((no_icf)) +_Bool f3(char *s) +{ + return s != __builtin_strstr (s, "hello"); +} + +__attribute__((no_icf)) +_Bool f4() +{ + char *foo_f4(void); + char *t1 = foo_f4(); + char *t2 = __builtin_strstr (t1, "hello"); + _Bool t3 = t2 == t1; + return t3; +} + +__attribute__((no_icf)) +void f5(char *s) +{ + char *t1 = __builtin_strstr (s, "hello"); + void foo_f5(void); + if (t1 != s) + foo_f5(); +} + +/* Do not perform transform, since strlen (t) + is unknown. */ + +__attribute__((no_icf)) +_Bool f6(char *s, char *t) +{ + return __builtin_strstr (s, t) == s; +} + +/* Do not perform transform in this case, since + t1 doesn't have single use. */ + +__attribute__((no_icf)) +_Bool f7(char *s) +{ + void foo_f7(char *); + + char *t1 = __builtin_strstr (s, "hello"); + foo_f7 (t1); + return (t1 == s); +} + +/* { dg-final { scan-tree-dump-times "__builtin_memcmp" 5 "strlen" } } */ diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index 339812e91c0..67075f07e29 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -2222,6 +2222,90 @@ handle_char_store (gimple_stmt_iterator *gsi) return true; } +/* Try to fold strstr (s, t) eq/ne s to memcmp (s, t, strlen (t)) eq/ne 0. */ + +static void +fold_strstr_to_memcmp (tree rhs1, tree rhs2, gimple *stmt) +{ + if (TREE_CODE (rhs1) != SSA_NAME + || TREE_CODE (rhs2) != SSA_NAME) + return; + + gimple *call_stmt = NULL; + for (int pass = 0; pass < 2; pass++) + { + gimple *g = SSA_NAME_DEF_STMT (rhs1); + if (gimple_call_builtin_p (g, BUILT_IN_STRSTR) + && has_single_use (rhs1) + && gimple_call_arg (g, 0) == rhs2) + { + call_stmt = g; + break; + } + std::swap (rhs1, rhs2); + } + + if (call_stmt) + { + tree arg0 = gimple_call_arg (call_stmt, 0); + + if (arg0 == rhs2) + { + tree arg1 = gimple_call_arg (call_stmt, 1); + tree arg1_len = NULL_TREE; + int idx = get_stridx (arg1); + + if (idx) + { + if (idx < 0) + arg1_len = build_int_cst (size_type_node, ~idx); + else + { + strinfo *si = get_strinfo (idx); + if (si) + arg1_len = get_string_length (si); + } + } + + if (arg1_len != NULL_TREE) + { + gimple_stmt_iterator gsi = gsi_for_stmt (call_stmt); + tree memcmp_decl = builtin_decl_explicit (BUILT_IN_MEMCMP); + gcall *memcmp_call = gimple_build_call (memcmp_decl, 3, + arg0, arg1, arg1_len); + tree memcmp_lhs = make_ssa_name (integer_type_node); + gimple_set_vuse (memcmp_call, gimple_vuse (call_stmt)); + gimple_call_set_lhs (memcmp_call, memcmp_lhs); + gsi_remove (&gsi, true); + gsi_insert_before (&gsi, memcmp_call, GSI_SAME_STMT); + tree zero = build_zero_cst (TREE_TYPE (memcmp_lhs)); + + if (is_gimple_assign (stmt)) + { + if (gimple_assign_rhs_code (stmt) == COND_EXPR) + { + tree cond = gimple_assign_rhs1 (stmt); + TREE_OPERAND (cond, 0) = memcmp_lhs; + TREE_OPERAND (cond, 1) = zero; + } + else + { + gimple_assign_set_rhs1 (stmt, memcmp_lhs); + gimple_assign_set_rhs2 (stmt, zero); + } + } + else + { + gcond *cond = as_a (stmt); + gimple_cond_set_lhs (cond, memcmp_lhs); + gimple_cond_set_rhs (cond, zero); + } + update_stmt (stmt); + } + } + } +} + /* Attempt to optimize a single statement at *GSI using string length knowledge. */ @@ -2302,7 +2386,23 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi) else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) handle_pointer_plus (gsi); } - else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs)) + else if (TREE_CODE (lhs) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (lhs))) + { + enum tree_code code = gimple_assign_rhs_code (stmt); + if (code == COND_EXPR) + { + tree cond = gimple_assign_rhs1 (stmt); + enum tree_code cond_code = TREE_CODE (cond); + + if (cond_code == EQ_EXPR || cond_code == NE_EXPR) + fold_strstr_to_memcmp (TREE_OPERAND (cond, 0), + TREE_OPERAND (cond, 1), stmt); + } + else if (code == EQ_EXPR || code == NE_EXPR) + fold_strstr_to_memcmp (gimple_assign_rhs1 (stmt), + gimple_assign_rhs2 (stmt), stmt); + } + else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs)) { tree type = TREE_TYPE (lhs); if (TREE_CODE (type) == ARRAY_TYPE) @@ -2316,6 +2416,13 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi) } } } + else if (gcond *cond = dyn_cast (stmt)) + { + enum tree_code code = gimple_cond_code (cond); + if (code == EQ_EXPR || code == NE_EXPR) + fold_strstr_to_memcmp (gimple_cond_lhs (stmt), + gimple_cond_rhs (stmt), stmt); + } if (gimple_vdef (stmt)) maybe_invalidate (stmt);