From b9a012156bbf3b13eb16027c0a75c186f172366a Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Tue, 16 Dec 2008 03:35:01 +0000 Subject: Add initial support for back-scheduling address computations, especially in the case of addresses computed from loop induction variables. llvm-svn: 61075 --- llvm/lib/Target/X86/X86Subtarget.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'llvm/lib/Target/X86/X86Subtarget.cpp') diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp index 2924d33a3b7..3c8f489c372 100644 --- a/llvm/lib/Target/X86/X86Subtarget.cpp +++ b/llvm/lib/Target/X86/X86Subtarget.cpp @@ -93,6 +93,17 @@ const char *X86Subtarget::getBZeroEntry() const { return 0; } +/// getSpecialAddressLatency - For targets where it is beneficial to +/// backschedule instructions that compute addresses, return a value +/// indicating the number of scheduling cycles of backscheduling that +/// should be attempted. +unsigned X86Subtarget::getSpecialAddressLatency() const { + // For x86 out-of-order targets, back-schedule address computations so + // that loads and stores aren't blocked. + // This value was chosen arbitrarily. + return 200; +} + /// GetCpuIDAndInfo - Execute the specified cpuid and return the 4 values in the /// specified arguments. If we can't run cpuid on the host, return true. bool X86::GetCpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX, -- cgit v1.2.3