[PATCH] PR target/67850: Wrong call_used_regs used in aggregate_value_p

["H.J. Lu" <hjl.tools@gmail.com>]

On Tue, Oct 06, 2015 at 02:30:59PM +0200, Richard Biener wrote:
> On Tue, Oct 6, 2015 at 1:43 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> > Since targetm.expand_to_rtl_hook may be called to switch ABI, it should
> > be called for each function before expanding to RTL.  Otherwise, we may
> > use the stale information from compilation of the previous function.
> > aggregate_value_p uses call_used_regs.  aggregate_value_p is used by
> > IPA and return value optimization, which are called before
> > pass_expand::execute after RTL expansion starts.  We need to call
> > targetm.expand_to_rtl_hook early enough in cgraph_node::expand to make
> > sure that everything is in sync when RTL expansion starts.
> >
> > Tested on Linux/x86-64.  OK for trunk?
> 
> Hmm, I think set_cfun hook should handle this.  expand_to_rtl_hook shouldn't
> mess with per-function stuff.
> 
> Richard.
> 

I am testig this patch.  OK for trunk if there is no regresion?


H.J.
--
ix86_maybe_switch_abi is called to late during RTL expansion and we
use the stale information from compilation of the previous function.
aggregate_value_p uses call_used_regs.  aggregate_value_p is used by
IPA and return value optimization, which are called before
pass_expand::execute after RTL expansion starts.  Instead,
ix86_maybe_switch_abi should be merged with ix86_set_current_function.

	PR target/67850
	* config/i386/i386.c (ix86_set_current_function): Renamed
	to ...
	(ix86_set_current_function_1): This.
	(ix86_set_current_function): New. incorporate old
	ix86_set_current_function and ix86_maybe_switch_abi.
	(ix86_maybe_switch_abi): Removed.
	(TARGET_EXPAND_TO_RTL_HOOK): Likewise.
---
 gcc/config/i386/i386.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index d59b59b..a0adf3d 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -6222,7 +6222,7 @@ ix86_reset_previous_fndecl (void)
    FNDECL.  The argument might be NULL to indicate processing at top
    level, outside of any function scope.  */
 static void
-ix86_set_current_function (tree fndecl)
+ix86_set_current_function_1 (tree fndecl)
 {
   /* Only change the context if the function changes.  This hook is called
      several times in the course of compiling a function, and we don't want to
@@ -6262,6 +6262,23 @@ ix86_set_current_function (tree fndecl)
   ix86_previous_fndecl = fndecl;
 }
 
+static void
+ix86_set_current_function (tree fndecl)
+{
+  ix86_set_current_function_1 (fndecl);
+
+  if (!cfun)
+    return;
+
+  /* 64-bit MS and SYSV ABI have different set of call used registers.
+     Avoid expensive re-initialization of init_regs each time we switch
+     function context since this is needed only during RTL expansion.  */
+  if (TARGET_64BIT
+      && (call_used_regs[SI_REG]
+	  == (cfun->machine->call_abi == MS_ABI)))
+    reinit_regs ();
+}
+
 \f
 /* Return true if this goes in large data/bss.  */
 
@@ -7395,17 +7412,6 @@ ix86_call_abi_override (const_tree fndecl)
   cfun->machine->call_abi = ix86_function_abi (fndecl);
 }
 
-/* 64-bit MS and SYSV ABI have different set of call used registers.  Avoid
-   expensive re-initialization of init_regs each time we switch function context
-   since this is needed only during RTL expansion.  */
-static void
-ix86_maybe_switch_abi (void)
-{
-  if (TARGET_64BIT &&
-      call_used_regs[SI_REG] == (cfun->machine->call_abi == MS_ABI))
-    reinit_regs ();
-}
-
 /* Return 1 if pseudo register should be created and used to hold
    GOT address for PIC code.  */
 bool
@@ -53802,9 +53808,6 @@ ix86_operands_ok_for_move_multiple (rtx *operands, bool load,
 #undef TARGET_CAN_INLINE_P
 #define TARGET_CAN_INLINE_P ix86_can_inline_p
 
-#undef TARGET_EXPAND_TO_RTL_HOOK
-#define TARGET_EXPAND_TO_RTL_HOOK ix86_maybe_switch_abi
-
 #undef TARGET_LEGITIMATE_ADDRESS_P
 #define TARGET_LEGITIMATE_ADDRESS_P ix86_legitimate_address_p
 
-- 
2.4.3