builtins.c (expand_builtin_fputs): When deleting NOP calls to builtin fputs...

	* builtins.c (expand_builtin_fputs): When deleting NOP calls to
	builtin fputs, ensure we still evaluate the stream in case it
	has side-effects.

testsuite:
	* gcc.c-torture/execute/stdio-opt-1.c: New test.

From-SVN: r37162

4 files changed, 45 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6d3e052..fcc65c8 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2000-10-31  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* builtins.c (expand_builtin_fputs): When deleting NOP calls to
+	builtin fputs, ensure we still evaluate the stream in case it
+	has side-effects.
+
 2000-10-31  Jakub Jelinek  <jakub@redhat.com>
 
 	* expr.c (do_store_flag): Pass operand_mode instead of GET_MODE (op0)
diff --git a/gcc/builtins.c b/gcc/builtins.c
index e2acada..3304b68 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -2351,7 +2351,13 @@ expand_builtin_fputs (arglist, ignore)
   switch (compare_tree_int (len, 1))
     {
     case -1: /* length is 0, delete the call entirely .  */
-      return const0_rtx;
+      {
+	/* Evaluate and ignore the argument in case it has
+           side-effects.  */
+	expand_expr (TREE_VALUE (TREE_CHAIN (arglist)), const0_rtx,
+		     VOIDmode, EXPAND_NORMAL);
+	return const0_rtx;
+      }
     case 0: /* length is 1, call fputc.  */
       {
 	tree stripped_string = TREE_VALUE (arglist);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 33002ac..6097ca2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2000-10-31  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* gcc.c-torture/execute/stdio-opt-1.c: New test.
+
 2000-10-31  Jakub Jelinek  <jakub@redhat.com>
 
 	* g++.old-deja/g++.other/inline16.C: New test.
diff --git a/gcc/testsuite/gcc.c-torture/execute/stdio-opt-1.c b/gcc/testsuite/gcc.c-torture/execute/stdio-opt-1.c
new file mode 100644
index 0000000..aeb7302
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/stdio-opt-1.c
@@ -0,0 +1,28 @@
+/* Copyright (C) 2000  Free Software Foundation.
+
+   When eliminating NOP calls to builtin fputs, ensure that we still
+   evaluate the stream argument in case it has side effects.
+   Written by Kaveh R. Ghazi, 10/30/2000.  */
+
+#include <stdio.h>
+
+int main()
+{
+  FILE *s_array[3] = {stdout, NULL, stdout}, **s_ptr = s_array;
+  
+  /* Increment the stream pointer once.  */
+  fputs ("", *s_ptr++);
+
+  /* Increment the stream pointer a second time.  */
+  s_ptr++;
+
+  /* If we failed to increment the stream pointer twice, then the
+     stream passed in here will be NULL and we should crash.  */
+  fputs ("hello world\n", *s_ptr);
+  
+  /* Just in case, If *s_ptr is NULL abort anyway.  */
+  if (*s_ptr == 0)
+    abort();
+
+  return 0;
+}