[PATCH, rtl-opt, i386]: Backport fix for PR 58066, __tls_get_addr is called with misaligned stack on x86-64

[Uros Bizjak]

Attached patch backports fixes for PR 58066 to release branches.

2015-07-XX  Uros Bizjak  <ubiz...@gmail.com>

    Backport from mainline:
    2015-07-17  Uros Bizjak  <ubiz...@gmail.com>

    PR rtl-optimization/66891
    * calls.c (expand_call): Wrap precompute_register_parameters with
    NO_DEFER_POP/OK_DEFER_POP to prevent deferred pops.

    2015-07-15  Uros Bizjak  <ubiz...@gmail.com>

    PR target/58066
    * config/i386/i386.md (*tls_global_dynamic_64_<mode>): Depend on SP_REG.
    (*tls_local_dynamic_base_64_<mode>): Ditto.
    (*tls_local_dynamic_base_64_largepic): Ditto.
    (tls_global_dynamic_64_<mode>): Update expander pattern.
    (tls_local_dynamic_base_64_<mode>): Ditto.

    2015-07-15  Uros Bizjak  <ubiz...@gmail.com>

    PR rtl-optimization/58066
    * calls.c (expand_call): Precompute register parameters before stack

testsuite/ChangeLog:

2015-07-XX  Uros Bizjak  <ubiz...@gmail.com>

    Backport from mainline:
    2015-07-17  Uros Bizjak  <ubiz...@gmail.com>

    PR target/66891
    * gcc.target/i386/pr66891.c: New test.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}  for
all default languages, obj-c++ and go.

OK for branches?

Uros.

Index: calls.c
===================================================================
--- calls.c     (revision 226001)
+++ calls.c     (working copy)
@@ -3115,6 +3115,19 @@ expand_call (tree exp, rtx target, int ignore)
 
       compute_argument_addresses (args, argblock, num_actuals);
 
+      /* Stack is properly aligned, pops can't safely be deferred during
+        the evaluation of the arguments.  */
+      NO_DEFER_POP;
+
+      /* Precompute all register parameters.  It isn't safe to compute
+        anything once we have started filling any specific hard regs.
+        TLS symbols sometimes need a call to resolve.  Precompute
+        register parameters before any stack pointer manipulation
+        to avoid unaligned stack in the called function.  */
+      precompute_register_parameters (num_actuals, args, &reg_parm_seen);
+
+      OK_DEFER_POP;
+
       /* Perform stack alignment before the first push (the last arg).  */
       if (argblock == 0
           && adjusted_args_size.constant > reg_parm_stack_space
@@ -3155,10 +3168,6 @@ expand_call (tree exp, rtx target, int ignore)
 
       funexp = rtx_for_function_call (fndecl, addr);
 
-      /* Precompute all register parameters.  It isn't safe to compute anything
-        once we have started filling any specific hard regs.  */
-      precompute_register_parameters (num_actuals, args, &reg_parm_seen);
-
       if (CALL_EXPR_STATIC_CHAIN (exp))
        static_chain_value = expand_normal (CALL_EXPR_STATIC_CHAIN (exp));
       else
Index: testsuite/gcc.target/i386/pr66891.c
===================================================================
--- testsuite/gcc.target/i386/pr66891.c (revision 0)
+++ testsuite/gcc.target/i386/pr66891.c (working copy)
@@ -0,0 +1,16 @@
+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2" } */
+
+__attribute__((__stdcall__)) void fn1();
+
+int a;
+
+static void fn2() {
+  for (;;)
+    ;
+}
+
+void fn3() {
+  fn1(0);
+  fn2(a == 0);
+}