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| author | dim <dim@FreeBSD.org> | 2011-10-20 21:10:27 +0000 |
|---|---|---|
| committer | dim <dim@FreeBSD.org> | 2011-10-20 21:10:27 +0000 |
| commit | 7b3392326c40c3c20697816acae597ba7b3144eb (patch) | |
| tree | 2cbcf22585e99f8a87d12d5ff94f392c0d266819 /lib/Target/TargetRegisterInfo.cpp | |
| parent | 1176aa52646fe641a4243a246aa7f960c708a274 (diff) | |
| download | FreeBSD-src-7b3392326c40c3c20697816acae597ba7b3144eb.zip FreeBSD-src-7b3392326c40c3c20697816acae597ba7b3144eb.tar.gz | |
Vendor import of llvm release_30 branch r142614:
http://llvm.org/svn/llvm-project/llvm/branches/release_30@142614
Diffstat (limited to 'lib/Target/TargetRegisterInfo.cpp')
| -rw-r--r-- | lib/Target/TargetRegisterInfo.cpp | 49 |
1 files changed, 15 insertions, 34 deletions
diff --git a/lib/Target/TargetRegisterInfo.cpp b/lib/Target/TargetRegisterInfo.cpp index 90a8f8d..67239b8 100644 --- a/lib/Target/TargetRegisterInfo.cpp +++ b/lib/Target/TargetRegisterInfo.cpp @@ -98,44 +98,25 @@ BitVector TargetRegisterInfo::getAllocatableSet(const MachineFunction &MF, } const TargetRegisterClass * -llvm::getCommonSubClass(const TargetRegisterClass *A, - const TargetRegisterClass *B) { - // First take care of the trivial cases +TargetRegisterInfo::getCommonSubClass(const TargetRegisterClass *A, + const TargetRegisterClass *B) const { + // First take care of the trivial cases. if (A == B) return A; if (!A || !B) return 0; - // If B is a subclass of A, it will be handled in the loop below - if (B->hasSubClass(A)) - return A; + // Register classes are ordered topologically, so the largest common + // sub-class it the common sub-class with the smallest ID. + const unsigned *SubA = A->getSubClassMask(); + const unsigned *SubB = B->getSubClassMask(); - const TargetRegisterClass *Best = 0; - for (TargetRegisterClass::sc_iterator I = A->subclasses_begin(); - const TargetRegisterClass *X = *I; ++I) { - if (X == B) - return B; // B is a subclass of A - - // X must be a common subclass of A and B - if (!B->hasSubClass(X)) - continue; - - // A superclass is definitely better. - if (!Best || Best->hasSuperClass(X)) { - Best = X; - continue; - } - - // A subclass is definitely worse - if (Best->hasSubClass(X)) - continue; - - // Best and *I have no super/sub class relation - pick the larger class, or - // the smaller spill size. - int nb = std::distance(Best->begin(), Best->end()); - int ni = std::distance(X->begin(), X->end()); - if (ni>nb || (ni==nb && X->getSize() < Best->getSize())) - Best = X; - } - return Best; + // We could start the search from max(A.ID, B.ID), but we are only going to + // execute 2-3 iterations anyway. + for (unsigned Base = 0, BaseE = getNumRegClasses(); Base < BaseE; Base += 32) + if (unsigned Common = *SubA++ & *SubB++) + return getRegClass(Base + CountTrailingZeros_32(Common)); + + // No common sub-class exists. + return NULL; } |
