[PATCH] Avoid an unused stack frame for -mprofile-kernel profiling on leaf functions.

[Anton Blanchard]

gcc/:

2014-09-25  Anton Blanchard  <an...@samba.org>

        PR target/63354
        * config/rs6000/rs6000.c (rs6000_keep_leaf_when_profiled): New function.
        * config/rs6000/linux64.h (TARGET_KEEP_LEAF_WHEN_PROFILED): Define.
---
 gcc/config/rs6000/linux64.h | 3 +++
 gcc/config/rs6000/rs6000.c  | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
index 39a2b17..415345b 100644
--- a/gcc/config/rs6000/linux64.h
+++ b/gcc/config/rs6000/linux64.h
@@ -59,6 +59,9 @@ extern int dot_symbols;
 
 #define TARGET_PROFILE_KERNEL profile_kernel
 
+#undef TARGET_KEEP_LEAF_WHEN_PROFILED
+#define TARGET_KEEP_LEAF_WHEN_PROFILED rs6000_keep_leaf_when_profiled
+
 #define TARGET_USES_LINUX64_OPT 1
 #ifdef HAVE_LD_LARGE_TOC
 #undef TARGET_CMODEL
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 16847aa..4e33e7b 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -23997,6 +23997,15 @@ rs6000_output_function_prologue (FILE *file,
   rs6000_pic_labelno++;
 }
 
+/* -mprofile-kernel code calls mcount before the function prolog,
+   so a profiled leaf function should stay a leaf function.  */
+
+static bool
+rs6000_keep_leaf_when_profiled ()
+{
+  return TARGET_PROFILE_KERNEL;
+}
+
 /* Non-zero if vmx regs are restored before the frame pop, zero if
    we restore after the pop when possible.  */
 #define ALWAYS_RESTORE_ALTIVEC_BEFORE_POP 0
-- 
1.9.1