From 97ac78dfb802599862e9b4ba15f02babd6093903 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Thu, 30 Mar 2023 00:00:56 -0700
Subject: [PATCH] bitops: use builtins directly

The compiler_bs{r,f}{32,64} macros serve no real purpose.  In bitops.h,
just use the builtins directly.
---
 include/wimlib/bitops.h   | 36 ++++--------------------------------
 include/wimlib/compiler.h |  6 ------
 2 files changed, 4 insertions(+), 38 deletions(-)

diff --git a/include/wimlib/bitops.h b/include/wimlib/bitops.h
index 7cca2f22..e5c4872e 100644
--- a/include/wimlib/bitops.h
+++ b/include/wimlib/bitops.h
@@ -40,27 +40,13 @@
 static forceinline unsigned
 bsr32(u32 v)
 {
-#ifdef compiler_bsr32
-	return compiler_bsr32(v);
-#else
-	unsigned bit = 0;
-	while ((v >>= 1) != 0)
-		bit++;
-	return bit;
-#endif
+	return 31 - __builtin_clz(v);
 }
 
 static forceinline unsigned
 bsr64(u64 v)
 {
-#ifdef compiler_bsr64
-	return compiler_bsr64(v);
-#else
-	unsigned bit = 0;
-	while ((v >>= 1) != 0)
-		bit++;
-	return bit;
-#endif
+	return 63 - __builtin_clzll(v);
 }
 
 static forceinline unsigned
@@ -82,27 +68,13 @@ bsrw(machine_word_t v)
 static forceinline unsigned
 bsf32(u32 v)
 {
-#ifdef compiler_bsf32
-	return compiler_bsf32(v);
-#else
-	unsigned bit;
-	for (bit = 0; !(v & 1); bit++, v >>= 1)
-		;
-	return bit;
-#endif
+	return __builtin_ctz(v);
 }
 
 static forceinline unsigned
 bsf64(u64 v)
 {
-#ifdef compiler_bsf64
-	return compiler_bsf64(v);
-#else
-	unsigned bit;
-	for (bit = 0; !(v & 1); bit++, v >>= 1)
-		;
-	return bit;
-#endif
+	return __builtin_ctzll(v);
 }
 
 static forceinline unsigned
diff --git a/include/wimlib/compiler.h b/include/wimlib/compiler.h
index ddb7a0e6..7f48e4fe 100644
--- a/include/wimlib/compiler.h
+++ b/include/wimlib/compiler.h
@@ -168,12 +168,6 @@
 #  define compiler_bswap64 __builtin_bswap64
 #endif
 
-/* (Optional) Find Last Set bit and Find First Set bit macros.  */
-#define compiler_bsr32(n)	(31 - __builtin_clz(n))
-#define compiler_bsr64(n)	(63 - __builtin_clzll(n))
-#define compiler_bsf32(n)	__builtin_ctz(n)
-#define compiler_bsf64(n)	__builtin_ctzll(n)
-
 /* Optional definitions for checking with 'sparse'.  */
 #ifdef __CHECKER__
 #  define _bitwise_attr	__attribute__((bitwise))
-- 
2.43.0