From: Georg-Johann Lay <avr@gjlay.de>
Date: Mon, 16 May 2011 14:16:22 +0000 (+0000)
Subject: re PR target/45099 ([avr] Warning could be issued for use of register variables that... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f24a5190c25a90ec8734ce62b68c081681a314fe;p=gcc.git

re PR target/45099 ([avr] Warning could be issued for use of register variables that will fail.)

	PR target/45099
	* config/avr/avr.c (avr_function_arg_advance): Error if a fixed
	register is needed for a function argument.

From-SVN: r173791
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 084fb0ef27e..b8af4fb3ede 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-05-16  Georg-Johann Lay  <avr@gjlay.de>
+
+	PR target/45099
+	* config/avr/avr.c (avr_function_arg_advance): Error if a fixed
+	register is needed for a function argument.
+
 2011-05-16  Richard Guenther  <rguenther@suse.de>
 
 	* gimple.c (struct type_hash_pair): New type.
diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c
index ac4b3182d81..c8c363ad948 100644
--- a/gcc/config/avr/avr.c
+++ b/gcc/config/avr/avr.c
@@ -1796,6 +1796,20 @@ avr_function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode,
       cfun->machine->sibcall_fails = 1;
     }
 
+  /* Test if all registers needed by the ABI are actually available.  If the
+     user has fixed a GPR needed to pass an argument, an (implicit) function
+     call would clobber that fixed register.  See PR45099 for an example.  */
+  
+  if (cum->regno >= 0)
+    {
+      int regno;
+
+      for (regno = cum->regno; regno < cum->regno + bytes; regno++)
+        if (fixed_regs[regno])
+          error ("Register %s is needed to pass a parameter but is fixed",
+                 reg_names[regno]);
+    }
+      
   if (cum->nregs <= 0)
     {
       cum->nregs = 0;