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Handle multi-word regsiters in REG_CFA_RESTORE notes

Message ID 4E7B9C2E.2090102@codesourcery.com
State New
Headers show

Commit Message

Bernd Schmidt Sept. 22, 2011, 8:35 p.m. UTC 
On 09/21/11 19:33, Richard Henderson wrote:
> Why, then, is this the only place in dwarf2cfi that needs to handle
> registers via a loop over nregs?  It seems to me that we should either
> be handling multi-register spans everywhere or nowhere.
> 
> Because alternately, this could be a bug in your backend that you
> failed to add two RESTORE notes instead of just one...

Well, changing the backend works too. Patch below.


Bernd
* mips.c (mips_restore_reg): Split multiword registers for
	REG_CFA_RESTORE notes.
diff mbox

Patch

Index: gcc/config/mips/mips.c
===================================================================
--- gcc/config/mips/mips.c	(revision 178847)
+++ gcc/config/mips/mips.c	(working copy)
@@ -10286,16 +10286,28 @@  mips_epilogue_set_cfa (rtx reg, HOST_WID
 static void
 mips_restore_reg (rtx reg, rtx mem)
 {
+  enum machine_mode mode = GET_MODE (reg);
+  unsigned regno = REGNO (reg);
+
   /* There's no MIPS16 instruction to load $31 directly.  Load into
      $7 instead and adjust the return insn appropriately.  */
-  if (TARGET_MIPS16 && REGNO (reg) == RETURN_ADDR_REGNUM)
-    reg = gen_rtx_REG (GET_MODE (reg), GP_REG_FIRST + 7);
+  if (TARGET_MIPS16 && regno == RETURN_ADDR_REGNUM)
+    reg = gen_rtx_REG (mode, GP_REG_FIRST + 7);
+  else if (GET_MODE_SIZE (mode) != 8 || !mips_split_64bit_move_p (reg, mem))
+    mips_epilogue.cfa_restores
+      = alloc_reg_note (REG_CFA_RESTORE, reg, mips_epilogue.cfa_restores);
   else
-    mips_epilogue.cfa_restores = alloc_reg_note (REG_CFA_RESTORE, reg,
-						 mips_epilogue.cfa_restores);
+    {
+      rtx word1 = mips_subword (reg, true);
+      rtx word2 = mips_subword (reg, false);
+      mips_epilogue.cfa_restores
+	= alloc_reg_note (REG_CFA_RESTORE, word1, mips_epilogue.cfa_restores);
+      mips_epilogue.cfa_restores
+	= alloc_reg_note (REG_CFA_RESTORE, word2, mips_epilogue.cfa_restores);
+    }
 
-  mips_emit_save_slot_move (reg, mem, MIPS_EPILOGUE_TEMP (GET_MODE (reg)));
-  if (REGNO (reg) == REGNO (mips_epilogue.cfa_reg))
+  mips_emit_save_slot_move (reg, mem, MIPS_EPILOGUE_TEMP (mode));
+  if (regno == REGNO (mips_epilogue.cfa_reg))
     /* The CFA is currently defined in terms of the register whose
        value we have just restored.  Redefine the CFA in terms of
        the stack pointer.  */