[PATCH, ARM] Enable shrink-wrap for apcs frame

[Zhenqiang Chen]

Hi

The patch enables shrink-wrap for apcs frame.

Bootstrap and no make check regression in ARM, THUMB1 and THUMB2 modes.
No make check regression with "-g/-mapcs/-marm".
Build linux-3.14-rc7 without error.

Is it OK for next stage1?

Thanks!
-Zhenqiang

ChangeLog:
2014-03-25  Zhenqiang Chen  <zhenqiang.c...@linaro.org>

        * config/arm/arm.c (arm_option_override): Enable shrink-wrap for
        TARGET_APCS_FRAME.
        (arm_emit_multi_reg_pop): Set correct dwarf info.
        (arm_expand_epilogue_apcs_frame): Add more dwarf info.

testsuite/ChangeLog:
2014-03-25  Zhenqiang Chen  <zhenqiang.c...@linaro.org>

        * gcc.target/arm/shrink-wrap-alloca.c: New test case.
        * gcc.target/arm/shrink-wrap-sibcall.c: New test case.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 0240cc7..fa86942 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -2811,9 +2811,6 @@ arm_option_override (void)
      generate additional returns.  */
   if (optimize_function_for_size_p (cfun) && TARGET_THUMB2)
     flag_shrink_wrap = false;
-  /* TBD: Dwarf info for apcs frame is not handled yet.  */
-  if (TARGET_APCS_FRAME)
-    flag_shrink_wrap = false;

   /* We only support -mslow-flash-data on armv7-m targets.  */
   if (target_slow_flash_data
@@ -19840,7 +19837,14 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
     par = emit_insn (par);

   REG_NOTES (par) = dwarf;
-  if (!return_in_pc)
+
+  if (!emit_update)
+    {
+      /* SP is restored from stack.  So reset the frame info.  */
+      RTX_FRAME_RELATED_P (par) = 1;
+      add_reg_note (par, REG_CFA_DEF_CFA, stack_pointer_rtx);
+    }
+  else if (!return_in_pc)
     arm_add_cfa_adjust_cfa_note (par, UNITS_PER_WORD * num_regs,
                  stack_pointer_rtx, stack_pointer_rtx);
 }
@@ -27226,6 +27230,9 @@ arm_expand_epilogue_apcs_frame (bool really_return)
       REG_NOTES (insn) = alloc_reg_note (REG_CFA_RESTORE,
                                          gen_rtx_REG (SImode, IP_REGNUM),
                                          NULL_RTX);
+      arm_add_cfa_adjust_cfa_note (insn, UNITS_PER_WORD,
+                   stack_pointer_rtx,
+                   stack_pointer_rtx);
     }

   if (!really_return || (saved_regs_mask & (1 << PC_REGNUM)))
diff --git a/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
b/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
new file mode 100644
index 0000000..318240b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/shrink-wrap-alloca.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -g -mapcs " } */
+
+int *p;
+
+void
+test (int a)
+{
+  if (a > 0)
+    p = __builtin_alloca (4);
+}
diff --git a/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
b/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
new file mode 100644
index 0000000..2efe5d0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/shrink-wrap-sibcall.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -g -mapcs " } */
+
+unsigned char a, b, d, f, g;
+
+int test (void);
+
+int
+baz (int c)
+{
+  if (c == 0) return test ();
+  if (b & 1)
+    {
+      g = 0;
+      int e = (a & 0x0f) - (g & 0x0f);
+
+      if (!a)  b |= 0x80;
+      a = e + test ();
+     f = g/5 + a*3879 + b *2985;
+    }
+   else
+   {
+     f = g + a*39879 + b *25;
+   }
+  return test ();
+}