Richard Biener wrote:
>
> This folding should be added to gimple-fold.c:gimple_fold_builtin instead,
> the builtins.c foldings are purerly for folding to constants nowadays.
So is this better? It's a lot more verbose for something so simple...
Unfortunately match.pd doesn't support this kind of thing either.
Wilco
ChangeLog:
2016-04-19 Wilco Dijkstra <wdijk...@arm.com>
gcc/
* gcc/gimple-fold.c (gimple_fold_builtin_strchr):
New function to optimize strchr (s, 0) to strlen.
(gimple_fold_builtin): Add BUILT_IN_STRCHR case.
testsuite/
* gcc/testsuite/gcc.dg/strlenopt-20.c: Update test.
* gcc/testsuite/gcc.dg/strlenopt-21.c: Likewise.
* gcc/testsuite/gcc.dg/strlenopt-22.c: Likewise.
* gcc/testsuite/gcc.dg/strlenopt-26.c: Likewise.
* gcc/testsuite/gcc.dg/strlenopt-5.c: Likewise.
* gcc/testsuite/gcc.dg/strlenopt-7.c: Likewise.
* gcc/testsuite/gcc.dg/strlenopt-9.c: Likewise.
--
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index
eb130d048469f0b8196e565fed9a40de74b098bd..11dcf69fc919f066362f4f713db392d14b39764e
100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -1380,6 +1380,59 @@ gimple_fold_builtin_strncpy (gimple_stmt_iterator *gsi,
return true;
}
+/* Simplify strchr (str, 0) into str + strlen (str).
+ In general strlen is significantly faster than strchr
+ due to being a simpler operation. */
+static bool
+gimple_fold_builtin_strchr (gimple_stmt_iterator *gsi)
+{
+ gimple *stmt = gsi_stmt (*gsi);
+ tree str = gimple_call_arg (stmt, 0);
+ tree c = gimple_call_arg (stmt, 1);
+ location_t loc = gimple_location (stmt);
+
+ if (optimize_function_for_size_p (cfun))
+ return false;
+
+ if (!integer_zerop (c) || !gimple_call_lhs (stmt))
+ return false;
+
+ tree newstr;
+ tree strlen_fn = builtin_decl_implicit (BUILT_IN_STRLEN);
+
+ if (!strlen_fn)
+ return false;
+
+ /* Create newstr = strlen (str). */
+ gimple_seq stmts = NULL, stmts2;
+ gimple *repl = gimple_build_call (strlen_fn, 1, str);
+ gimple_set_location (repl, loc);
+ if (gimple_in_ssa_p (cfun))
+ newstr = make_ssa_name (size_type_node);
+ else
+ newstr = create_tmp_reg (size_type_node);
+ gimple_call_set_lhs (repl, newstr);
+ gimple_seq_add_stmt_without_update (&stmts, repl);
+
+ /* Create (str p+ strlen (str)). */
+ newstr = fold_build_pointer_plus_loc (loc, str, newstr);
+ newstr = force_gimple_operand (newstr, &stmts2, true, NULL_TREE);
+ gimple_seq_add_seq_without_update (&stmts, stmts2);
+
+ repl = gimple_build_assign (gimple_call_lhs (stmt), newstr);
+ gimple_seq_add_stmt_without_update (&stmts, repl);
+ gsi_replace_with_seq_vops (gsi, stmts);
+ /* gsi now points at the assignment to the lhs, get a
+ stmt iterator to the strlen.
+ ??? We can't use gsi_for_stmt as that doesn't work when the
+ CFG isn't built yet. */
+ gimple_stmt_iterator gsi2 = *gsi;
+ gsi_prev (&gsi2);
+ gsi_prev (&gsi2);
+ fold_stmt (&gsi2);
+ return true;
+}
+
/* Simplify a call to the strcat builtin. DST and SRC are the arguments
to the call.
@@ -2821,6 +2874,8 @@ gimple_fold_builtin (gimple_stmt_iterator *gsi)
gimple_call_arg (stmt, 1));
case BUILT_IN_STRNCAT:
return gimple_fold_builtin_strncat (gsi);
+ case BUILT_IN_STRCHR:
+ return gimple_fold_builtin_strchr (gsi);
case BUILT_IN_FPUTS:
return gimple_fold_builtin_fputs (gsi, gimple_call_arg (stmt, 0),
gimple_call_arg (stmt, 1), false);
diff --git a/gcc/testsuite/gcc.dg/strlenopt-20.c
b/gcc/testsuite/gcc.dg/strlenopt-20.c
index
a83e845c26d88e5acdcabf142f7b319136663488..7b483eaeac1aa47278111a92148a16f00b2aaa2d
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-20.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-20.c
@@ -86,9 +86,9 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 2 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 4 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-21.c
b/gcc/testsuite/gcc.dg/strlenopt-21.c
index
e22fa9fca9ba14354db2cd5f602283b64bd8dcac..05b85a49dde0a7f5d269174fd4269e40be910dbd
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-21.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-21.c
@@ -57,9 +57,9 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 2 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 3 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-22.c
b/gcc/testsuite/gcc.dg/strlenopt-22.c
index
aa55f5ebd6a2d4803ee9a7fd60fc538d86f47124..b4ef772f0e59252f10a5419ede6837b3c8ca8265
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-22.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-22.c
@@ -31,9 +31,9 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 3 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 4 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-26.c
b/gcc/testsuite/gcc.dg/strlenopt-26.c
index
4bd54bef540806ca90d2b9bcfc33eb531991c967..da2f465a5b5003fa5dca05f3a6ee00e97b98b5dd
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-26.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-26.c
@@ -21,4 +21,5 @@ main (void)
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 2 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-5.c
b/gcc/testsuite/gcc.dg/strlenopt-5.c
index
1b006a93045599a75bdb10a39e86ffa59b475c83..a24aea44e8b00ff7b35a907aaa941b4c509642c4
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-5.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-5.c
@@ -48,9 +48,9 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 2 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 2 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 2 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-7.c
b/gcc/testsuite/gcc.dg/strlenopt-7.c
index
3ae1e2cb3f0d08c8b05107c4e65b67bdb39cf7ab..aa53d7e75254dfe56c93172afc49f95e5b7901e6
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-7.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-7.c
@@ -40,11 +40,11 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 0 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 2 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 1 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "\\*r_\[0-9\]* = 0;" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "return 3;" 1 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-9.c
b/gcc/testsuite/gcc.dg/strlenopt-9.c
index
b0406b162d48fca375883035043b0c50b9db61a1..e5e276210ba4b7d75867605f1ecf5c06eb970ef5
100644
--- a/gcc/testsuite/gcc.dg/strlenopt-9.c
+++ b/gcc/testsuite/gcc.dg/strlenopt-9.c
@@ -98,10 +98,10 @@ main ()
return 0;
}
-/* { dg-final { scan-tree-dump-times "strlen \\(" 3 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strlen \\(" 5 "strlen" } } */
/* { dg-final { scan-tree-dump-times "memcpy \\(" 6 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcpy \\(" 1 "strlen" } } */
/* { dg-final { scan-tree-dump-times "strcat \\(" 0 "strlen" } } */
-/* { dg-final { scan-tree-dump-times "strchr \\(" 3 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "strchr \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "stpcpy \\(" 0 "strlen" } } */
/* { dg-final { scan-tree-dump-times "return 4;" 1 "optimized" } } */
