From: Richard Earnshaw <rearnsha@arm.com>
Date: Thu, 22 Dec 2011 14:28:39 +0000 (+0000)
Subject: re PR target/51643 (Incorrect code produced for tail-call of weak function with ... 
X-Git-Tag: releases/gcc-4.6.3~235
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=70f428a0bcff20d6bf9dd8013662fd434e620937;p=thirdparty%2Fgcc.git

re PR target/51643 (Incorrect code produced for tail-call of weak function with -O2/-O3 option)

	PR target/51643
	* arm.c (arm_function_ok_for_sibcall): Don't try to tailcall a
	weak function on bare-metal EABI targets.

	* gcc.target/arm/sibcall-2.c: New test.

From-SVN: r182622
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a11ac8a77794..cd22ed466177 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-12-21  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/51643
+	* arm.c (arm_function_ok_for_sibcall): Don't try to tailcall a
+	weak function on bare-metal EABI targets.
+
 2011-12-21  Uros Bizjak  <ubizjak@gmail.com>
 
 	Backport from mainline
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index b79de0892f07..f271320c80e3 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -5077,6 +5077,14 @@ arm_function_ok_for_sibcall (tree decl, tree exp)
   if (IS_STACKALIGN (func_type))
     return false;
 
+  /* The AAPCS says that, on bare-metal, calls to unresolved weak
+     references should become a NOP.  Don't convert such calls into
+     sibling calls.  */
+  if (TARGET_AAPCS_BASED
+      && arm_abi == ARM_ABI_AAPCS
+      && lookup_attribute ("weak", DECL_ATTRIBUTES (decl)))
+    return false;
+
   /* Everything else is ok.  */
   return true;
 }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6071d1f609b4..86ca26fccf47 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-12-21  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/51643
+	* gcc.target/arm/sibcall-2.c: New test.
+
 2011-12-19  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/51583
diff --git a/gcc/testsuite/gcc.target/arm/sibcall-2.c b/gcc/testsuite/gcc.target/arm/sibcall-2.c
new file mode 100644
index 000000000000..921c0f30284b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/sibcall-2.c
@@ -0,0 +1,12 @@
+/* { dg-require-effective-target arm_eabi } */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mabi=aapcs" } */
+
+
+extern void __attribute__((weak)) wfunc(void);
+void main(void)
+{
+  wfunc();  /* Must not tail-call.  */
+}
+
+/* { dg-final { scan-assembler-not "b\[\\t \]+wfunc" } } */