From: David Given <dg@cowlark.com>
Date: Sat, 4 Feb 2017 21:56:13 +0000 (+0100)
Subject: Calculate the worst-case weight of a register in a register class.
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=21f015fd328d0b306b12753a8ba7a74631c0cb58;p=ack.git

Calculate the worst-case weight of a register in a register class.
---

diff --git a/util/mcgg/mcgg.h b/util/mcgg/mcgg.h
index 9ddf922c8..6aa304f7d 100644
--- a/util/mcgg/mcgg.h
+++ b/util/mcgg/mcgg.h
@@ -66,6 +66,7 @@ struct burm_regclass_data
     const char* name;
     const struct burm_register_data** registers;
     burm_register_bitmap_t bitmap;
+    int weight;
 };
 
 extern const struct burm_register_data burm_register_data[];
diff --git a/util/mcgg/registers.c b/util/mcgg/registers.c
index 5d7818851..c26cbd36d 100644
--- a/util/mcgg/registers.c
+++ b/util/mcgg/registers.c
@@ -132,19 +132,21 @@ void analyse_registers(void)
 			real_registers[real_register_count++] = r;
 	}
 
-	/* Set the register bitmaps. */
+	/* Set the register bitmaps and weight. */
 
 	for (i=0; i<real_register_count; i++)
 	{
 		struct reg* r = real_registers[i];
 		r->bitmap = bitmap_alloc(real_register_count);
 		bitmap_set(r->bitmap, real_register_count, i);
+		r->weight = 1;
 	}
 
 	for (i=0; i<fake_register_count; i++)
 	{
 		struct reg* r = fake_registers[i];
 		r->bitmap = bitmap_alloc(real_register_count);
+		r->weight = r->uses.count;
 
 		for (j=0; j<r->uses.count; j++)
 		{
@@ -174,6 +176,9 @@ void analyse_registers(void)
 			{
 				struct regattr* rc = sit.item;
 				bitmap_or(rc->bitmap, real_register_count, r->bitmap);
+
+				if (r->weight > rc->weight)
+					rc->weight = r->weight;
 			}
 		}
 	}
@@ -237,7 +242,9 @@ void emitregisterattrs(void)
 		{
 			print("0x%x, ", rc->bitmap[j]);
 		}
-		print("}},\n");
+		print("}, ");
+		print("%d,", rc->weight);
+		print("},\n");
 		printh("#define %P%s_ATTR (1U<<%d)\n", rc->name, rc->number);
 	}
 	print("};\n\n");
diff --git a/util/mcgg/registers.h b/util/mcgg/registers.h
index 3aaf3eb1a..6b0bc4381 100644
--- a/util/mcgg/registers.h
+++ b/util/mcgg/registers.h
@@ -13,6 +13,7 @@ struct reg
 	struct stringlist* names;  /* register names */
 	unsigned int* bitmap;      /* hardware register bitmap */
 	ARRAYOF(struct reg) uses;  /* registers that this one uses */
+	int weight;                /* weight of this register */
 };
 
 struct regattr
@@ -20,6 +21,7 @@ struct regattr
 	const char* name;      /* class name */
 	int number;            /* identifying number */
 	unsigned int* bitmap;  /* hardware register bitmap */
+	int weight;            /* maximum weight of all registers in this class */
 };
 
 extern struct reg* makereg(const char* name);