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Add a version of FindUnusedReg that restrict search to a specific set of registers.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34784 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-03-01 08:56:24 +00:00
parent f49407b790
commit 5196b3680c
2 changed files with 20 additions and 0 deletions
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5
include/llvm/CodeGen/RegisterScavenging.h
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@ -78,6 +78,11 @@ public:
void setUnused(unsigned Reg) { RegStates.set(Reg); }
void setUnused(BitVector Regs) { RegStates |= Regs; }
/// FindUnusedReg - Find a unused register of the specified register class
/// from the specified set of registers. It return 0 is none is found.
unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
const BitVector &Candidates) const;
/// FindUnusedReg - Find a unused register of the specified register class.
/// Exclude callee saved registers if directed. It return 0 is none is found.
unsigned FindUnusedReg(const TargetRegisterClass *RegClass,

15
lib/CodeGen/RegisterScavenging.cpp
View File

@ -156,6 +156,21 @@ static void CreateRegClassMask(const TargetRegisterClass *RC, BitVector &Mask) {
Mask.set(*I);
}
unsigned RegScavenger::FindUnusedReg(const TargetRegisterClass *RegClass,
const BitVector &Candidates) const {
// Mask off the registers which are not in the TargetRegisterClass.
BitVector RegStatesCopy(NumPhysRegs, false);
CreateRegClassMask(RegClass, RegStatesCopy);
RegStatesCopy &= RegStates;
// Restrict the search to candidates.
RegStatesCopy &= Candidates;
// Returns the first unused (bit is set) register, or 0 is none is found.
int Reg = RegStatesCopy.find_first();
return (Reg == -1) ? 0 : Reg;
}
unsigned RegScavenger::FindUnusedReg(const TargetRegisterClass *RegClass,
bool ExCalleeSaved) const {
// Mask off the registers which are not in the TargetRegisterClass.