diff mbox

[AArch64] Remove aarch64_frame_pointer_required

Message ID DB6PR0801MB2053E2F66E6E4BBB94298ED7838D0@DB6PR0801MB2053.eurprd08.prod.outlook.com
State New
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Commit Message

Wilco Dijkstra Aug. 15, 2017, 4:24 p.m. UTC 
ping


From: Wilco Dijkstra
Sent: 04 August 2017 13:41
To: GCC Patches; James Greenhalgh
Cc: nd
Subject: [PATCH][AArch64] Remove aarch64_frame_pointer_required
    
To implement -fomit-leaf-frame-pointer, there are 2 places where we need
to check whether we have to use a frame chain (since register allocation
may allocate LR in a leaf function that omits the frame pointer, but if
LR is spilled we must emit a frame chain).  To simplify this do not force
frame_pointer_needed via aarch64_frame_pointer_required, but enable the
frame chain in aarch64_layout_frame.  Now aarch64_frame_pointer_required
can be removed and aarch64_can_eliminate is simplified.

OK for commit?

ChangeLog:
2017-08-03  Wilco Dijkstra  <wdijkstr@arm.com>

    gcc/
        * config/aarch64/aarch64.c (aarch64_frame_pointer_required)
        Remove.
        (aarch64_layout_frame): Initialise emit_frame_chain.
        (aarch64_can_eliminate): Remove omit leaf frame pointer code.
        (TARGET_FRAME_POINTER_REQUIRED): Remove define.
--
diff mbox

Patch

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index aa71a410106164bb8da808a4b513771d713bb0f0..9bbc9864fd47a4404a80ea0cd5608202e8d0726a 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -2836,21 +2836,6 @@  aarch64_output_probe_stack_range (rtx reg1, rtx reg2)
   return "";
 }
 
-static bool
-aarch64_frame_pointer_required (void)
-{
-  /* Use the frame pointer if enabled and it is not a leaf function, unless
-     leaf frame pointer omission is disabled.  If the frame pointer is enabled,
-     force the frame pointer in leaf functions which use LR.  */
-  if (flag_omit_frame_pointer == 2
-      && !(flag_omit_leaf_frame_pointer
-          && crtl->is_leaf
-          && !df_regs_ever_live_p (LR_REGNUM)))
-    return true;
-
-  return false;
-}
-
 /* Mark the registers that need to be saved by the callee and calculate
    the size of the callee-saved registers area and frame record (both FP
    and LR may be omitted).  */
@@ -2867,6 +2852,14 @@  aarch64_layout_frame (void)
   cfun->machine->frame.emit_frame_chain
     = frame_pointer_needed || crtl->calls_eh_return;
 
+  /* Emit a frame chain if the frame pointer is enabled.
+     If -momit-leaf-frame-pointer is used, do not use a frame chain
+     in leaf functions which do not use LR.  */
+  if (flag_omit_frame_pointer == 2
+      && !(flag_omit_leaf_frame_pointer && crtl->is_leaf
+          && !df_regs_ever_live_p (LR_REGNUM)))
+    cfun->machine->frame.emit_frame_chain = true;
+
 #define SLOT_NOT_REQUIRED (-2)
 #define SLOT_REQUIRED     (-1)
 
@@ -5884,17 +5877,6 @@  aarch64_can_eliminate (const int from, const int to)
 
       return false;
     }
-  else
-    {
-      /* If we decided that we didn't need a leaf frame pointer but then used
-        LR in the function, then we'll want a frame pointer after all, so
-        prevent this elimination to ensure a frame pointer is used.  */
-      if (to == STACK_POINTER_REGNUM
-         && flag_omit_frame_pointer == 2
-         && flag_omit_leaf_frame_pointer
-         && df_regs_ever_live_p (LR_REGNUM))
-       return false;
-    }
 
   return true;
 }
@@ -15385,9 +15367,6 @@  aarch64_run_selftests (void)
 #undef TARGET_FUNCTION_VALUE_REGNO_P
 #define TARGET_FUNCTION_VALUE_REGNO_P aarch64_function_value_regno_p
 
-#undef TARGET_FRAME_POINTER_REQUIRED
-#define TARGET_FRAME_POINTER_REQUIRED aarch64_frame_pointer_required
-
 #undef TARGET_GIMPLE_FOLD_BUILTIN
 #define TARGET_GIMPLE_FOLD_BUILTIN aarch64_gimple_fold_builtin