Date: Fri, 25 May 2012 17:15:53 +0000 (UTC) From: Marius Strobl <marius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r236012 - stable/9/contrib/compiler-rt/lib Message-ID: <201205251715.q4PHFrlo023223@svn.freebsd.org>
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Author: marius Date: Fri May 25 17:15:53 2012 New Revision: 236012 URL: http://svn.freebsd.org/changeset/base/236012 Log: MFC: r230021 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. Modified: stable/9/contrib/compiler-rt/lib/int_lib.h Directory Properties: stable/9/contrib/compiler-rt/ (props changed) Modified: stable/9/contrib/compiler-rt/lib/int_lib.h ============================================================================== --- stable/9/contrib/compiler-rt/lib/int_lib.h Fri May 25 17:14:47 2012 (r236011) +++ stable/9/contrib/compiler-rt/lib/int_lib.h Fri May 25 17:15:53 2012 (r236012) @@ -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 */
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