ReMat of load from stub in pic mode extends the life of pic base. Currently spiller doesn't do a good job of estimating the impact. Disable for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index ffe2083..c9de586 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -37,6 +37,10 @@
cl::desc("Print instructions that the allocator wants to"
" fuse, but the X86 backend currently can't"),
cl::Hidden);
+ cl::opt<bool>
+ ReMatPICStubLoad("remat-pic-stub-load",
+ cl::desc("Re-materialize load from stub in PIC mode"),
+ cl::init(false), cl::Hidden);
}
X86InstrInfo::X86InstrInfo(X86TargetMachine &tm)
@@ -782,6 +786,8 @@
if (BaseReg == 0)
return true;
// Allow re-materialization of PIC load.
+ if (!ReMatPICStubLoad && MI->getOperand(4).isGlobal())
+ return false;
MachineRegisterInfo &MRI = MI->getParent()->getParent()->getRegInfo();
bool isPICBase = false;
for (MachineRegisterInfo::def_iterator I = MRI.def_begin(BaseReg),