PR 69246: Invalid REG_ARGS_SIZE for sibcalls

The problem in this PR was that we were treating a sibcall as popping
arguments, leading to a negative REG_ARGS_SIZE.

It doesn't really make sense to treat sibcalls as popping since
(a) they're deallocating the caller's stack, not ours, and
(b) there are no optabs for popping sibcalls (any more).

Tested on x86_64-linux-gnu.

gcc/
	PR middle-end/69246
	* calls.c (emit_call_1): Force n_popped to zero for sibcalls.

gcc/testsuite/
	PR middle-end/69246
	* gcc.target/i386/pr69246.c: New test.

From-SVN: r232428

gcc/ChangeLog

+2016-01-15  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR middle-end/69246
+	* calls.c (emit_call_1): Force n_popped to zero for sibcalls.
+
 2016-01-15  Ilya Enkovich  <enkovich.gnu@gmail.com>
 
 	* config/i386/i386.c (scalar_chain::compute_convert_gain): Fix typo.

gcc/calls.c

@@ -272,12 +272,19 @@ emit_call_1 (rtx funexp, tree fntree ATTRIBUTE_UNUSED, tree fndecl ATTRIBUTE_UNU
   rtx rounded_stack_size_rtx = GEN_INT (rounded_stack_size);
   rtx call, funmem, pat;
   int already_popped = 0;
-  HOST_WIDE_INT n_popped
-    = targetm.calls.return_pops_args (fndecl, funtype, stack_size);
+  HOST_WIDE_INT n_popped = 0;
+
+  /* Sibling call patterns never pop arguments (no sibcall(_value)_pop
+     patterns exist).  Any popping that the callee does on return will
+     be from our caller's frame rather than ours.  */
+  if (!(ecf_flags & ECF_SIBCALL))
+    {
+      n_popped += targetm.calls.return_pops_args (fndecl, funtype, stack_size);
 
 #ifdef CALL_POPS_ARGS
-  n_popped += CALL_POPS_ARGS (*get_cumulative_args (args_so_far));
+      n_popped += CALL_POPS_ARGS (*get_cumulative_args (args_so_far));
 #endif
+    }
 
   /* Ensure address is valid.  SYMBOL_REF is already valid, so no need,
      and we don't want to load it into a register as an optimization,

gcc/testsuite/ChangeLog

+2016-01-15  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR middle-end/69246
+	* gcc.target/i386/pr69246.c: New test.
+
 2016-01-15  Dominik Vogt  <vogt@linux.vnet.ibm.com>
 
 	* gfortran.dg/bind_c_array_params_2.f90: Fix test patterns for

gcc/testsuite/gcc.target/i386/pr69246.c

+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2" } */
+
+void (__attribute__ ((stdcall)) *a) (int);
+
+void __attribute__ ((stdcall))
+foo (int x)
+{
+  a (x);
+}
+
+int (__attribute__ ((stdcall)) *b) (int);
+
+int __attribute__ ((stdcall))
+bar (int x)
+{
+  return b (x);
+}