Use std::bitset for SubtargetFeatures.
Previously, subtarget features were a bitfield with the underlying type being uint64_t.
Since several targets (X86 and ARM, in particular) have hit or were very close to hitting this bound, switching the features to use a bitset.
No functional change.
The first several times this was committed (e.g. r229831, r233055), it caused several buildbot failures.
Apparently the reason for most failures was both clang and gcc's inability to deal with large numbers (> 10K) of bitset constructor calls in tablegen-generated initializers of instruction info tables.
This should now be fixed.
llvm-svn: 238192
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index 008aeff..f20318d 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -265,8 +265,8 @@
}
// NEON f32 ops are non-IEEE 754 compliant. Darwin is ok with it by default.
- uint64_t Bits = getFeatureBits();
- if ((Bits & ARM::ProcA5 || Bits & ARM::ProcA8) && // Where this matters
+ const FeatureBitset &Bits = getFeatureBits();
+ if ((Bits[ARM::ProcA5] || Bits[ARM::ProcA8]) && // Where this matters
(Options.UnsafeFPMath || isTargetDarwin()))
UseNEONForSinglePrecisionFP = true;
}