be: Factorise the code for ia32 to match an immediate.

Other backends can use this, too.
This also corrects the bug, that for Address+Const immediates the check, whether it is a tls entity, was missing.

ir/be/betranshlp.c

@@ -14,6 +14,7 @@
 #include "belive.h"
 #include "benode.h"
 #include "betranshlp.h"
+#include "beutil.h"
 #include "cgana.h"
 #include "debug.h"
 #include "execfreq_t.h"
@@ -872,3 +873,43 @@ ir_node *be_skip_sameconv(ir_node *node)
 	}
 	return node;
 }
+
+bool be_match_immediate(ir_node const *const node, ir_tarval **const tarval_out, ir_entity **const entity_out)
+{
+	ir_node const *addr;
+	ir_node const *cnst;
+	if (is_Const(node)) {
+		addr = NULL;
+		cnst = node;
+	} else if (is_Address(node)) {
+		addr = node;
+		cnst = NULL;
+	} else if (is_Add(node)) {
+		ir_node const *const l = get_Add_left(node);
+		ir_node const *const r = get_Add_right(node);
+		if (is_Address(l) && is_Const(r)) {
+			addr = l;
+			cnst = r;
+		} else if (is_Const(l) && is_Address(r)) {
+			addr = r;
+			cnst = l;
+		} else {
+			return false;
+		}
+	} else {
+		return false;
+	}
+
+	ir_entity *entity;
+	if (addr) {
+		entity = get_Address_entity(addr);
+		if (is_tls_entity(entity))
+			return false;
+	} else {
+		entity = NULL;
+	}
+
+	*tarval_out = cnst ? get_Const_tarval(cnst) : NULL;
+	*entity_out = entity;
+	return true;
+}

ir/be/betranshlp.h

@@ -157,4 +157,6 @@ ir_node *be_skip_downconv(ir_node *node, bool single_user);
 /** Skip all signedness convs */
 ir_node *be_skip_sameconv(ir_node *node);
 
+bool be_match_immediate(ir_node const *node, ir_tarval **tarval_out, ir_entity **entity_out);
+
 #endif

ir/be/ia32/x86_asm.c

@@ -22,7 +22,6 @@
 #include "beirg.h"
 #include "benode.h"
 #include "betranshlp.h"
-#include "beutil.h"
 #include "gen_ia32_regalloc_if.h"
 #include "ia32_new_nodes.h"
 #include "irprintf.h"
@@ -279,37 +278,15 @@ bool x86_match_immediate(x86_imm32_t *immediate, const ir_node *node,
 	if (get_mode_arithmetic(mode) != irma_twos_complement)
 		return false;
 
-	const ir_node *cnst;
-	ir_entity     *entity;
-	if (is_Const(node)) {
-		cnst   = node;
-		entity = NULL;
-	} else if (is_Address(node)) {
-		cnst   = NULL;
-		entity = get_Address_entity(node);
-		if (is_tls_entity(entity))
-			return false;
-	} else if (is_Add(node)) {
-		ir_node *left  = get_Add_left(node);
-		ir_node *right = get_Add_right(node);
-		if (is_Const(left) && is_Address(right)) {
-			cnst   = left;
-			entity = get_Address_entity(right);
-		} else if (is_Address(left) && is_Const(right)) {
-			cnst   = right;
-			entity = get_Address_entity(left);
-		} else {
-			return false;
-		}
-	} else {
+	ir_tarval *offset;
+	ir_entity *entity;
+	if (!be_match_immediate(node, &offset, &entity))
 		return false;
-	}
 
 	long val = 0;
-	if (cnst != NULL) {
-		ir_tarval *offset = get_Const_tarval(cnst);
+	if (offset) {
 		if (!tarval_is_long(offset)) {
-			be_warningf(cnst, "tarval is not long");
+			be_warningf(node, "tarval is not long");
 			return false;
 		}