From 9c769a65e92b891c96d6f9088b55a450164964c3 Mon Sep 17 00:00:00 2001
From: Alan Lawrence <alan.lawrence@arm.com>
Date: Mon, 6 Jul 2015 16:21:55 +0000
Subject: [PATCH] [ARM] fix movdi expander to avoid illegal ldrd/strd

        * config/arm/arm.md (movdi): Avoid odd-number ldrd/strd in ARM state.

From-SVN: r225461
---
 gcc/ChangeLog         |  4 ++++
 gcc/config/arm/arm.md | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d3929fa41f6..82755498c17 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2015-07-06  Alan Lawrence  <alan.lawrence@arm.com>
+
+	* config/arm/arm.md (movdi): Avoid odd-number ldrd/strd in ARM state.
+
 2015-07-06  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/66772
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 1ac8af099ce..be51c77dd8e 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -5481,6 +5481,42 @@
       if (!REG_P (operands[0]))
 	operands[1] = force_reg (DImode, operands[1]);
     }
+  if (REG_P (operands[0]) && REGNO (operands[0]) < FIRST_VIRTUAL_REGISTER
+      && !HARD_REGNO_MODE_OK (REGNO (operands[0]), DImode))
+    {
+      /* Avoid LDRD's into an odd-numbered register pair in ARM state
+	 when expanding function calls.  */
+      gcc_assert (can_create_pseudo_p ());
+      if (MEM_P (operands[1]) && MEM_VOLATILE_P (operands[1]))
+	{
+	  /* Perform load into legal reg pair first, then move.  */
+	  rtx reg = gen_reg_rtx (DImode);
+	  emit_insn (gen_movdi (reg, operands[1]));
+	  operands[1] = reg;
+	}
+      emit_move_insn (gen_lowpart (SImode, operands[0]),
+		      gen_lowpart (SImode, operands[1]));
+      emit_move_insn (gen_highpart (SImode, operands[0]),
+		      gen_highpart (SImode, operands[1]));
+      DONE;
+    }
+  else if (REG_P (operands[1]) && REGNO (operands[1]) < FIRST_VIRTUAL_REGISTER
+	   && !HARD_REGNO_MODE_OK (REGNO (operands[1]), DImode))
+    {
+      /* Avoid STRD's from an odd-numbered register pair in ARM state
+	 when expanding function prologue.  */
+      gcc_assert (can_create_pseudo_p ());
+      rtx split_dest = (MEM_P (operands[0]) && MEM_VOLATILE_P (operands[0]))
+		       ? gen_reg_rtx (DImode)
+		       : operands[0];
+      emit_move_insn (gen_lowpart (SImode, split_dest),
+		      gen_lowpart (SImode, operands[1]));
+      emit_move_insn (gen_highpart (SImode, split_dest),
+		      gen_highpart (SImode, operands[1]));
+      if (split_dest != operands[0])
+	emit_insn (gen_movdi (operands[0], split_dest));
+      DONE;
+    }
   "
 )