re PR middle-end/37843 (unaligned stack in main due to tail call optimization)

gcc/

2008-11-25  H.J. Lu  <hongjiu.lu@intel.com>
	    Joey Ye  <joey.ye@intel.com>

	PR middle-end/37843
	* config/i386/i386.c (ix86_function_ok_for_sibcall): Return
	false if we need to align the outgoing stack.
	(ix86_update_stack_boundary): Check parm_stack_boundary.

gcc/testsuite/

2008-11-25  H.J. Lu  <hongjiu.lu@intel.com>

	PR middle-end/37843
	* gcc.target/i386/align-main-3.c: New.
	* gcc.target/i386/pr37843-1.c: Likewise.
	* gcc.target/i386/pr37843-2.c: Likewise.
	* gcc.target/i386/pr37843-3.c: Likewise.

Co-Authored-By: Joey Ye <joey.ye@intel.com>

From-SVN: r142193

gcc/ChangeLog

+2008-11-25  H.J. Lu  <hongjiu.lu@intel.com>
+	    Joey Ye  <joey.ye@intel.com>
+
+	PR middle-end/37843
+	* config/i386/i386.c (ix86_function_ok_for_sibcall): Return
+	false if we need to align the outgoing stack.
+	(ix86_update_stack_boundary): Check parm_stack_boundary.
+
 2008-11-25  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/38151

gcc/config/i386/i386.c

@@ -4112,6 +4112,11 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
       && ix86_function_regparm (TREE_TYPE (decl), NULL) >= 3)
     return false;
 
+  /* If we need to align the outgoing stack, then sibcalling would
+     unalign the stack, which may break the called function.  */
+  if (ix86_incoming_stack_boundary < PREFERRED_STACK_BOUNDARY)
+    return false;
+
   /* Otherwise okay.  That also includes certain types of indirect calls.  */
   return true;
 }
@@ -7770,6 +7775,11 @@ ix86_update_stack_boundary (void)
 			   TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl))))
     ix86_incoming_stack_boundary = MIN_STACK_BOUNDARY;
 
+  /* The incoming stack frame has to be aligned at least at
+     parm_stack_boundary.  */
+  if (ix86_incoming_stack_boundary < crtl->parm_stack_boundary)
+    ix86_incoming_stack_boundary = crtl->parm_stack_boundary;
+
   /* Stack at entrance of main is aligned by runtime.  We use the
      smallest incoming stack boundary. */
   if (ix86_incoming_stack_boundary > MAIN_STACK_BOUNDARY

gcc/testsuite/ChangeLog

+2008-11-25  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR middle-end/37843
+	* gcc.target/i386/align-main-3.c: New.
+	* gcc.target/i386/pr37843-1.c: Likewise.
+	* gcc.target/i386/pr37843-2.c: Likewise.
+	* gcc.target/i386/pr37843-3.c: Likewise.
+
 2008-11-25  Mikael Morin  <mikael.morin@tele2.fr>
 
 	PR fortran/36463

gcc/testsuite/gcc.target/i386/align-main-3.c

+/* Test for stack alignment with sibcall optimization.  */
+/* { dg-do compile { target { *-*-linux* && ilp32 } } } */
+/* { dg-options "-O2 -mpreferred-stack-boundary=4 -mincoming-stack-boundary=2" } */
+/* { dg-final { scan-assembler "andl\[\\t \]*\\$-16,\[\\t \]*%\[re\]?sp" } } */
+/* { dg-final { scan-assembler "call\[\\t \]*foo" } } */
+/* { dg-final { scan-assembler-not "jmp\[\\t \]*foo" } } */
+
+extern int foo (void);
+
+int
+main ()
+{
+  return foo ();
+}

gcc/testsuite/gcc.target/i386/pr37843-1.c

+/* Test for stack alignment with sibcall optimization.  */
+/* { dg-options "-O2 -mpreferred-stack-boundary=6 -mincoming-stack-boundary=5" } */
+/* { dg-final { scan-assembler "and\[lq\]?\[\\t \]*\\$-64,\[\\t \]*%\[re\]?sp" } } */
+/* { dg-final { scan-assembler "call\[\\t \]*foo" } } */
+/* { dg-final { scan-assembler-not "jmp\[\\t \]*foo" } } */
+
+extern int foo (void);
+
+int bar (void)
+{
+    return foo();
+}

gcc/testsuite/gcc.target/i386/pr37843-2.c

+/* Test for stack alignment with sibcall optimization.  */
+/* { dg-options "-O2 -mpreferred-stack-boundary=6 -mincoming-stack-boundary=6" } */
+/* { dg-final { scan-assembler-not "and\[lq\]?\[\\t \]*\\$-64,\[\\t \]*%\[re\]?sp" } } */
+/* { dg-final { scan-assembler-not "call\[\\t \]*foo" } } */
+/* { dg-final { scan-assembler "jmp\[\\t \]*foo" } } */
+
+extern int foo (void);
+
+int bar (void)
+{
+    return foo();
+}

gcc/testsuite/gcc.target/i386/pr37843-3.c

+/* Test for stack alignment with sibcall optimization.  */
+/* { dg-do compile { target { *-*-linux* && ilp32 } } } */
+/* { dg-options "-O2 -std=gnu99 -mpreferred-stack-boundary=4 -mincoming-stack-boundary=2" } */
+/* { dg-final { scan-assembler-not "andl\[\\t \]*\\$-16,\[\\t \]*%\[re\]?sp" } } */
+/* { dg-final { scan-assembler-not "call\[\\t \]*foo" } } */
+/* { dg-final { scan-assembler "jmp\[\\t \]*foo" } } */
+
+extern int foo (_Decimal128);
+
+int bar (_Decimal128 x)
+{
+    return foo(x);
+}