[X86] Tune LEA usage for Silvermont
According to Intel Software Optimization Manual on Silvermont in some cases LEA
is better to be replaced with ADD instructions:
"The rule of thumb for ADDs and LEAs is that it is justified to use LEA
with a valid index and/or displacement for non-destructive destination purposes
(especially useful for stack offset cases), or to use a SCALE.
Otherwise, ADD(s) are preferable."
Differential Revision: http://reviews.llvm.org/D3826
llvm-svn: 209198
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 6a28547..efb5c70 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -1728,12 +1728,8 @@
return true;
}
-/// isSafeToClobberEFLAGS - Return true if it's safe insert an instruction that
-/// would clobber the EFLAGS condition register. Note the result may be
-/// conservative. If it cannot definitely determine the safety after visiting
-/// a few instructions in each direction it assumes it's not safe.
-static bool isSafeToClobberEFLAGS(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator I) {
+bool X86InstrInfo::isSafeToClobberEFLAGS(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator I) const {
MachineBasicBlock::iterator E = MBB.end();
// For compile time consideration, if we are not able to determine the