From 4eb5f7b6cf7e62db40780d3ada330204ed5a23d3 Mon Sep 17 00:00:00 2001 From: aurel32 Date: Sun, 5 Apr 2009 20:08:50 +0000 Subject: tcg/x86_64: optimize register allocation order The beginning of the register allocation order list on the TCG x86_64 target matches the list of clobbered registers. This means that when an helper is called, there is almost always clobbered registers that have to be spilled. The same way register %rsi and %rdi are at the top of the register allocation order list, while they can't be used for load/store operations. This means the data and/or address registers are very often %rsi and %rdi, and their values have to be spilled, and then moved back to another register. This patches changes to the allocation order to avoid those effects. It results in a 8% gain speed in qemu-x86_64 to compress a bzip2 file, and a 6% gain in qemu-system-mips64 to compile a small application. Signed-off-by: Aurelien Jarno git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7003 c046a42c-6fe2-441c-8c8c-71466251a162 --- tcg/x86_64/tcg-target.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/tcg/x86_64/tcg-target.c b/tcg/x86_64/tcg-target.c index 92f0733efe..5378e8510b 100644 --- a/tcg/x86_64/tcg-target.c +++ b/tcg/x86_64/tcg-target.c @@ -44,22 +44,21 @@ static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = { #endif static const int tcg_target_reg_alloc_order[] = { - TCG_REG_RDI, - TCG_REG_RSI, - TCG_REG_RDX, - TCG_REG_RCX, - TCG_REG_R8, - TCG_REG_R9, - TCG_REG_RAX, - TCG_REG_R10, - TCG_REG_R11, - TCG_REG_RBP, TCG_REG_RBX, TCG_REG_R12, TCG_REG_R13, TCG_REG_R14, TCG_REG_R15, + TCG_REG_R10, + TCG_REG_R11, + TCG_REG_R9, + TCG_REG_R8, + TCG_REG_RCX, + TCG_REG_RDX, + TCG_REG_RSI, + TCG_REG_RDI, + TCG_REG_RAX, }; static const int tcg_target_call_iarg_regs[6] = { -- cgit v1.2.3