[RFC,ivopts] ARM - Make ivopts take into account whether pre and post increments are actually supported on targets.

Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
--- gcc/tree-ssa-loop-ivopts.c	(revision 187327)
+++ gcc/tree-ssa-loop-ivopts.c	(working copy)
@@ -2362,8 +2362,12 @@ 
   cstepi = int_cst_value (step);
 
   mem_mode = TYPE_MODE (TREE_TYPE (*use->op_p));
-  if ((HAVE_PRE_INCREMENT && GET_MODE_SIZE (mem_mode) == cstepi)
-      || (HAVE_PRE_DECREMENT && GET_MODE_SIZE (mem_mode) == -cstepi))
+  if (((USE_LOAD_PRE_INCREMENT (mem_mode)
+	|| USE_STORE_PRE_INCREMENT (mem_mode))
+       && GET_MODE_SIZE (mem_mode) == cstepi)
+      || ((USE_LOAD_PRE_DECREMENT (mem_mode)
+	   || USE_STORE_PRE_DECREMENT (mem_mode))
+	  && GET_MODE_SIZE (mem_mode) == -cstepi))
     {
       enum tree_code code = MINUS_EXPR;
       tree new_base;
@@ -2380,8 +2384,12 @@ 
       add_candidate_1 (data, new_base, step, important, IP_BEFORE_USE, use,
 		       use->stmt);
     }
-  if ((HAVE_POST_INCREMENT && GET_MODE_SIZE (mem_mode) == cstepi)
-      || (HAVE_POST_DECREMENT && GET_MODE_SIZE (mem_mode) == -cstepi))
+  if (((USE_LOAD_POST_INCREMENT (mem_mode)
+	|| USE_STORE_POST_INCREMENT (mem_mode))
+       && GET_MODE_SIZE (mem_mode) == cstepi)
+      || ((USE_LOAD_POST_DECREMENT (mem_mode)
+	   || USE_STORE_POST_DECREMENT (mem_mode))
+	  && GET_MODE_SIZE (mem_mode) == -cstepi))
     {
       add_candidate_1 (data, base, step, important, IP_AFTER_USE, use,
 		       use->stmt);
@@ -3315,25 +3323,29 @@ 
       reg0 = gen_raw_REG (address_mode, LAST_VIRTUAL_REGISTER + 1);
       reg1 = gen_raw_REG (address_mode, LAST_VIRTUAL_REGISTER + 2);
 
-      if (HAVE_PRE_DECREMENT)
+      if (USE_LOAD_PRE_DECREMENT (mem_mode) 
+	  || USE_STORE_PRE_DECREMENT (mem_mode))
 	{
 	  addr = gen_rtx_PRE_DEC (address_mode, reg0);
 	  has_predec[mem_mode]
 	    = memory_address_addr_space_p (mem_mode, addr, as);
 	}
-      if (HAVE_POST_DECREMENT)
+      if (USE_LOAD_POST_DECREMENT (mem_mode) 
+	  || USE_STORE_POST_DECREMENT (mem_mode))
 	{
 	  addr = gen_rtx_POST_DEC (address_mode, reg0);
 	  has_postdec[mem_mode]
 	    = memory_address_addr_space_p (mem_mode, addr, as);
 	}
-      if (HAVE_PRE_INCREMENT)
+      if (USE_LOAD_PRE_INCREMENT (mem_mode) 
+	  || USE_STORE_PRE_DECREMENT (mem_mode))
 	{
 	  addr = gen_rtx_PRE_INC (address_mode, reg0);
 	  has_preinc[mem_mode]
 	    = memory_address_addr_space_p (mem_mode, addr, as);
 	}
-      if (HAVE_POST_INCREMENT)
+      if (USE_LOAD_POST_INCREMENT (mem_mode) 
+	  || USE_STORE_POST_INCREMENT (mem_mode))
 	{
 	  addr = gen_rtx_POST_INC (address_mode, reg0);
 	  has_postinc[mem_mode]
Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c	(revision 187327)
+++ gcc/config/arm/arm.c	(working copy)
@@ -25886,5 +25886,51 @@ 
   return ret;
 }
 
-
+bool
+arm_autoinc_modes_ok_p (enum machine_mode mode, enum arm_auto_incmodes code)
+{
+  /* If we are soft float and we do not have ldrd 
+     then all auto increment forms are ok.  */
+  if (TARGET_SOFT_FLOAT && (TARGET_LDRD || GET_MODE_SIZE (mode) <= 4))
+    return true;
+
+  switch (code)
+    {
+      /* Post increment and Pre Decrement are supported for all
+	 instruction forms except for vector forms.  */
+    case ARM_POST_INC:
+    case ARM_PRE_DEC:
+      if (VECTOR_MODE_P (mode))
+	{
+	  if (code != ARM_PRE_DEC)
+	    return true;
+	  else 
+	    return false;
+	}
+      
+      return true;
+
+    case ARM_POST_DEC:
+    case ARM_PRE_INC:
+      /* Without LDRD and mode size greater than 
+	 word size, there is no point in auto-incrementing
+         because ldm and stm will not have these forms.  */
+      if (!TARGET_LDRD && GET_MODE_SIZE (mode) > 4)
+	return false;
+
+      /* Vector and floating point modes do not support
+	 these auto increment forms.  */
+      if (FLOAT_MODE_P (mode) || VECTOR_MODE_P (mode))
+	return false;
+
+      return true;
+     
+    default:
+      return false;
+      
+    }
+
+  return false;
+}
+
 #include "gt-arm.h"
Index: gcc/config/arm/arm.h
===================================================================
--- gcc/config/arm/arm.h	(revision 187327)
+++ gcc/config/arm/arm.h	(working copy)
@@ -1613,6 +1613,30 @@ 
 #define HAVE_PRE_MODIFY_REG   TARGET_32BIT
 #define HAVE_POST_MODIFY_REG  TARGET_32BIT
 
+enum arm_auto_incmodes
+  {
+    ARM_POST_INC,
+    ARM_PRE_INC,
+    ARM_POST_DEC,
+    ARM_PRE_DEC
+  };
+
+#define ARM_AUTOINC_VALID_FOR_MODE_P(mode, code) \
+  (TARGET_32BIT && arm_autoinc_modes_ok_p (mode, code))
+#define USE_LOAD_POST_INCREMENT(mode) \
+  ARM_AUTOINC_VALID_FOR_MODE_P(mode, ARM_POST_INC)
+#define USE_LOAD_PRE_INCREMENT(mode)  \
+  ARM_AUTOINC_VALID_FOR_MODE_P(mode, ARM_PRE_INC)
+#define USE_LOAD_POST_DECREMENT(mode) \
+  ARM_AUTOINC_VALID_FOR_MODE_P(mode, ARM_POST_DEC)
+#define USE_LOAD_PRE_DECREMENT(mode)  \
+  ARM_AUTOINC_VALID_FOR_MODE_P(mode, ARM_PRE_DEC)
+
+#define USE_STORE_PRE_DECREMENT(mode) USE_LOAD_PRE_DECREMENT(mode)
+#define USE_STORE_PRE_INCREMENT(mode) USE_LOAD_PRE_INCREMENT(mode)
+#define USE_STORE_POST_DECREMENT(mode) USE_LOAD_POST_DECREMENT(mode)
+#define USE_STORE_POST_INCREMENT(mode) USE_LOAD_POST_INCREMENT(mode)
+
 /* Macros to check register numbers against specific register classes.  */
 
 /* These assume that REGNO is a hard or pseudo reg number.
Index: gcc/config/arm/arm-protos.h
===================================================================
--- gcc/config/arm/arm-protos.h	(revision 187327)
+++ gcc/config/arm/arm-protos.h	(working copy)
@@ -250,4 +250,6 @@ 
 extern void arm_expand_vec_perm (rtx target, rtx op0, rtx op1, rtx sel);
 extern bool arm_expand_vec_perm_const (rtx target, rtx op0, rtx op1, rtx sel);
 
+extern bool arm_autoinc_modes_ok_p (enum machine_mode, enum arm_auto_incmodes);
+
 #endif /* ! GCC_ARM_PROTOS_H */