From: Wilco Dijkstra <wdijkstr@arm.com>
Date: Wed, 8 Nov 2017 15:36:34 +0000 (+0000)
Subject: [AArch64] Simplify aarch64_can_eliminate
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6216fd904f46a11fa243195ee303560dc802958e;p=gcc.git

[AArch64] Simplify aarch64_can_eliminate

Simplify aarch64_can_eliminate - if we need a frame pointer, we must
eliminate to HARD_FRAME_POINTER_REGNUM.  Rather than hardcoding all
combinations from the ELIMINABLE_REGS list, just do the correct check.

    gcc/
	* config/aarch64/aarch64.c (aarch64_can_eliminate): Simplify logic.

From-SVN: r254534
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d39de6b0320..e546a12d09f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2017-11-08  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* config/aarch64/aarch64.c (aarch64_can_eliminate): Simplify logic.
+
 2017-11-08  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	* config/aarch64/aarch64.c (aarch64_frame_pointer_required)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index f58f192273e..0c67e2b5c67 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5913,26 +5913,14 @@ aarch64_secondary_reload (bool in_p ATTRIBUTE_UNUSED, rtx x,
 }
 
 static bool
-aarch64_can_eliminate (const int from, const int to)
+aarch64_can_eliminate (const int from ATTRIBUTE_UNUSED, const int to)
 {
-  /* If we need a frame pointer, we must eliminate FRAME_POINTER_REGNUM into
-     HARD_FRAME_POINTER_REGNUM and not into STACK_POINTER_REGNUM.  */
+  gcc_assert (from == ARG_POINTER_REGNUM || from == FRAME_POINTER_REGNUM);
 
+  /* If we need a frame pointer, ARG_POINTER_REGNUM and FRAME_POINTER_REGNUM
+     can only eliminate to HARD_FRAME_POINTER_REGNUM.  */
   if (frame_pointer_needed)
-    {
-      if (from == ARG_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
-	return true;
-      if (from == ARG_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
-	return false;
-      if (from == FRAME_POINTER_REGNUM && to == STACK_POINTER_REGNUM
-	  && !cfun->calls_alloca)
-	return true;
-      if (from == FRAME_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
-	return true;
-
-      return false;
-    }
-
+    return to == HARD_FRAME_POINTER_REGNUM;
   return true;
 }