Add a TRI::getLargestLegalSuperClass hook to provide an upper limit on register class inflation.
The hook will be used by the register allocator when recomputing register
classes after removing constraints.
Thumb1 code doesn't allow anything larger than tGPR, and x86 needs to ensure
that the spill size doesn't change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130228 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 6eb9002..ea1f08a 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -342,6 +342,25 @@
return false;
}
+const TargetRegisterClass*
+ARMBaseRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC)
+ const {
+ const TargetRegisterClass *Super = RC;
+ TargetRegisterClass::sc_iterator I = RC->superclasses_begin();
+ do {
+ switch (Super->getID()) {
+ case ARM::GPRRegClassID:
+ case ARM::SPRRegClassID:
+ case ARM::DPRRegClassID:
+ case ARM::QPRRegClassID:
+ case ARM::QQPRRegClassID:
+ case ARM::QQQQPRRegClassID:
+ return Super;
+ }
+ Super = *I++;
+ } while (Super);
+ return RC;
+}
const TargetRegisterClass *
ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {