Avoid going through another folding cycle and use the ignore flag to
directly transform BUILT_IN_STPCPY_CHK to BUILT_IN_STRCPY when set,
likewise for BUILT_IN_STPNCPY_CHK to BUILT_IN_STPNCPY.
Dump the transformation in dump_file so that we can verify in tests that
the direct transformation actually happened.
gcc/ChangeLog:
* gimple-fold.c (gimple_fold_builtin_stxcpy_chk,
gimple_fold_builtin_stxncpy_chk): Use BUILT_IN_STRNCPY if return
value is not used.
gcc/testsuite/ChangeLog:
* gcc.dg/fold-stringops.c: New test.
Signed-off-by: Siddhesh Poyarekar <siddh...@gotplt.org>
---
gcc/gimple-fold.c | 50 +++++++++++++++++--------
gcc/testsuite/gcc.dg/fold-stringops-1.c | 23 ++++++++++++
2 files changed, 57 insertions(+), 16 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/fold-stringops-1.c
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 6e25a7c05db..92e15784803 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -3088,6 +3088,19 @@ gimple_fold_builtin_memory_chk (gimple_stmt_iterator
*gsi,
return true;
}
+static void
+dump_transformation (gimple *from, gimple *to)
+{
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "transformed ");
+ print_generic_expr (dump_file, gimple_call_fn (from), dump_flags);
+ fprintf (dump_file, " to ");
+ print_generic_expr (dump_file, gimple_call_fn (to), dump_flags);
+ fprintf (dump_file, "\n");
+ }
+}
+
/* Fold a call to the __st[rp]cpy_chk builtin.
DEST, SRC, and SIZE are the arguments to the call.
IGNORE is true if return value can be ignored. FCODE is the BUILT_IN_*
@@ -3184,12 +3197,13 @@ gimple_fold_builtin_stxcpy_chk (gimple_stmt_iterator
*gsi,
}
/* If __builtin_st{r,p}cpy_chk is used, assume st{r,p}cpy is available. */
- fn = builtin_decl_explicit (fcode == BUILT_IN_STPCPY_CHK
+ fn = builtin_decl_explicit (fcode == BUILT_IN_STPCPY_CHK && !ignore
? BUILT_IN_STPCPY : BUILT_IN_STRCPY);
if (!fn)
return false;
gimple *repl = gimple_build_call (fn, 2, dest, src);
+ dump_transformation (stmt, repl);
replace_call_with_call_and_fold (gsi, repl);
return true;
}
@@ -3209,19 +3223,6 @@ gimple_fold_builtin_stxncpy_chk (gimple_stmt_iterator
*gsi,
bool ignore = gimple_call_lhs (stmt) == NULL_TREE;
tree fn;
- if (fcode == BUILT_IN_STPNCPY_CHK && ignore)
- {
- /* If return value of __stpncpy_chk is ignored,
- optimize into __strncpy_chk. */
- fn = builtin_decl_explicit (BUILT_IN_STRNCPY_CHK);
- if (fn)
- {
- gimple *repl = gimple_build_call (fn, 4, dest, src, len, size);
- replace_call_with_call_and_fold (gsi, repl);
- return true;
- }
- }
-
if (! tree_fits_uhwi_p (size))
return false;
@@ -3234,7 +3235,23 @@ gimple_fold_builtin_stxncpy_chk (gimple_stmt_iterator
*gsi,
For MAXLEN only allow optimizing into non-_ocs function
if SIZE is >= MAXLEN, never convert to __ocs_fail (). */
if (maxlen == NULL_TREE || ! tree_fits_uhwi_p (maxlen))
- return false;
+ {
+ if (fcode == BUILT_IN_STPNCPY_CHK && ignore)
+ {
+ /* If return value of __stpncpy_chk is ignored,
+ optimize into __strncpy_chk. */
+ fn = builtin_decl_explicit (BUILT_IN_STRNCPY_CHK);
+ if (fn)
+ {
+ gimple *repl = gimple_build_call (fn, 4, dest, src, len,
+ size);
+ replace_call_with_call_and_fold (gsi, repl);
+ return true;
+ }
+ }
+
+ return false;
+ }
}
else
maxlen = len;
@@ -3244,12 +3261,13 @@ gimple_fold_builtin_stxncpy_chk (gimple_stmt_iterator
*gsi,
}
/* If __builtin_st{r,p}ncpy_chk is used, assume st{r,p}ncpy is available. */
- fn = builtin_decl_explicit (fcode == BUILT_IN_STPNCPY_CHK
+ fn = builtin_decl_explicit (fcode == BUILT_IN_STPNCPY_CHK && !ignore
? BUILT_IN_STPNCPY : BUILT_IN_STRNCPY);
if (!fn)
return false;
gimple *repl = gimple_build_call (fn, 3, dest, src, len);
+ dump_transformation (stmt, repl);
replace_call_with_call_and_fold (gsi, repl);
return true;
}
diff --git a/gcc/testsuite/gcc.dg/fold-stringops-1.c
b/gcc/testsuite/gcc.dg/fold-stringops-1.c
new file mode 100644
index 00000000000..712dd369e7c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-stringops-1.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-lower-details" } */
+
+char dst[2048];
+
+char *
+copy1 (const char *src, int cond)
+{
+ __builtin___stpncpy_chk (dst, src, 42, __builtin_object_size (dst, 0));
+
+ return dst;
+}
+
+char *
+copy2 (void)
+{
+ __builtin___stpcpy_chk (dst, "Hello world", __builtin_object_size (dst, 0));
+
+ return dst;
+}
+/* { dg-final { scan-tree-dump "transformed __builtin___stpncpy_chk to
__builtin_strncpy" "lower" } } */
+/* { dg-final { scan-tree-dump "transformed __builtin___stpcpy_chk to
__builtin_strcpy" "lower" } } */
+
--
2.31.1
