From a8c104fbb0feae30333ba287f5a98b6b5a8e813e Mon Sep 17 00:00:00 2001 From: Ed Schouten Date: Thu, 12 Jan 2012 16:51:56 +0000 Subject: [PATCH] Add a workaround to prevent endless recursion in compiler-rt. SPARC and MIPS CPUs don't have special instructions to count leading/trailing zeroes. The compiler-rt library provides fallback rountines for these. The 64-bit routines, __clzdi2 and __ctzdi2, are implemented as simple wrappers around the compiler built-in __builtin_clz(), assuming these will expand to either 32-bit CPU instructions or calls to __clzsi2 and __ctzsi2. Unfortunately, our GCC 4.2 probably thinks that because the operand is stored in a 64-bit register, it might just be a better idea to invoke its 64-bit equivalent, simply resulting into endless recursion. Fix this by defining __builtin_clz and __builtin_ctz to __clzsi2 and __ctzsi2 explicitly. --- contrib/compiler-rt/lib/int_lib.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/contrib/compiler-rt/lib/int_lib.h b/contrib/compiler-rt/lib/int_lib.h index a87426c513c..2328a1dca28 100644 --- a/contrib/compiler-rt/lib/int_lib.h +++ b/contrib/compiler-rt/lib/int_lib.h @@ -43,4 +43,24 @@ /* Include internal utility function declarations. */ #include "int_util.h" +/* + * Workaround for LLVM bug 11663. Prevent endless recursion in + * __c?zdi2(), where calls to __builtin_c?z() are expanded to + * __c?zdi2() instead of __c?zsi2(). + * + * Instead of placing this workaround in c?zdi2.c, put it in this + * global header to prevent other C files from making the detour + * through __c?zdi2() as well. + * + * This problem has only been observed on FreeBSD for sparc64 and + * mips64 with GCC 4.2.1. + */ +#if defined(__FreeBSD__) && (defined(__sparc64__) || \ + defined(__mips_n64) || defined(__mips_o64)) +si_int __clzsi2(si_int); +si_int __ctzsi2(si_int); +#define __builtin_clz __clzsi2 +#define __builtin_ctz __ctzsi2 +#endif + #endif /* INT_LIB_H */ -- 2.45.2