sparc.c (sparc_asm_function_epilogue): Don't output an extra nop past a sibling call...

        * config/sparc/sparc.c (sparc_asm_function_epilogue): Don't output
        an extra nop past a sibling call at the very end.

        testsuite/
        * gcc.target/sparc/sibcall-dslot.c: New testcase.

From-SVN: r163395

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a1c3658a2ab832eba5a5ce185dde9e1d605e4dec..31762851e516ca976cb8ae05ea06acc6951998cc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-08-20  Olivier Hainque  <hainque@adacore.com>
+
+       * config/sparc/sparc.c (sparc_asm_function_epilogue): Don't output
+       an extra nop past a sibling call at the very end.
+
 2010-08-19  Bernd Schmidt  <bernds@codesourcery.com>
 
        PR bootstrap/45350

diff --git a/gcc/config/sparc/sparc.c b/gcc/config/sparc/sparc.c
index ef1dd730eae7fa13e420f95454717e568fe960e0..50b981e749fa5630583de1924372e2dd71fe9a39 100644 (file)
--- a/gcc/config/sparc/sparc.c
+++ b/gcc/config/sparc/sparc.c
@@ -4527,11 +4527,11 @@ sparc_can_use_return_insn_p (void)
 static void
 sparc_asm_function_epilogue (FILE *file, HOST_WIDE_INT size ATTRIBUTE_UNUSED)
 {
-  /* If code does not drop into the epilogue, we have to still output
-     a dummy nop for the sake of sane backtraces.  Otherwise, if the
-     last two instructions of a function were "call foo; dslot;" this
-     can make the return PC of foo (i.e. address of call instruction
-     plus 8) point to the first instruction in the next function.  */
+  /* If the last two instructions of a function are "call foo; dslot;"
+     the return address might point to the first instruction in the next
+     function and we have to output a dummy nop for the sake of sane
+     backtraces in such cases.  This is pointless for sibling calls since
+     the return address is explicitly adjusted.  */
 
   rtx insn, last_real_insn;
 
@@ -4543,7 +4543,9 @@ sparc_asm_function_epilogue (FILE *file, HOST_WIDE_INT size ATTRIBUTE_UNUSED)
       && GET_CODE (PATTERN (last_real_insn)) == SEQUENCE)
     last_real_insn = XVECEXP (PATTERN (last_real_insn), 0, 0);
 
-  if (last_real_insn && GET_CODE (last_real_insn) == CALL_INSN)
+  if (last_real_insn
+      && CALL_P (last_real_insn)
+      && !SIBLING_CALL_P (last_real_insn))
     fputs("\tnop\n", file);
 
   sparc_output_deferred_case_vectors ();

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e8bbfc1e3b5c9f3659a3af0e5750f2b1e5e5b2d1..e46fd3f22dfab7a071225b27580c3b6064a97271 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2010-10-19  Olivier Hainque  <hainque@adacore.com>
+
+       * gcc.target/sparc/sibcall-dslot.c: New testcase.
+
 2010-08-19  Jason Merrill  <jason@redhat.com>
 
        * g++.dg/init/synth3.C: New.

diff --git a/gcc/testsuite/gcc.target/sparc/sibcall-dslot.c b/gcc/testsuite/gcc.target/sparc/sibcall-dslot.c
new file mode 100644 (file)
index 0000000..db34016
--- /dev/null
+++ b/gcc/testsuite/gcc.target/sparc/sibcall-dslot.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+extern int one ();
+
+int some_n ()
+{
+    return one ();
+}
+
+/* { dg-final { scan-assembler-not "nop" } } */