This improves code generation for mul[us]64 for all hosts. In the case of ia64 and s390x we see immediate benefit as we get to use the native 128-bit multiply insn. In the case of ppc64, we need a patch to gcc to enable this; I hope to get such a patch into gcc 4.8.0, but it may have to wait for gcc 4.8.1.
In the case of 32-bit hosts like i386 and arm, the second patch enables better use of add-with-carry type insns. Examining both of these targets reveals smaller code that is also now branchless. Perhaps this ought to be considered for 1.4? r~ Richard Henderson (2): host-utils: Use __int128 for mul[us]64 host-utils: Improve mulu64 and muls64 configure | 20 +++++++++ include/qemu/host-utils.h | 17 ++++---- util/host-utils.c | 102 ++++++++++++++++++---------------------------- 3 files changed, 68 insertions(+), 71 deletions(-) -- 1.7.11.7
