[SILOptimizer] Add ‘llvm.cttz.*’ Intrinsic support to Constant Folding #23720
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rdar://problem/29522851
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@swift-ci Please test and merge |
| // Undefined | ||
| return nullptr; | ||
| } | ||
| LZ = LHSI.getBitWidth(); |
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Can you do an early exit here?
| } | ||
| LZ = LHSI.getBitWidth(); | ||
| } else { | ||
| switch (ID) { |
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My suggestion: Use an inline constructor:
unsigned LZ = [&] {
...
}();
Also. Do you really think we are going to support more types of intrinsics here? Why not just put in an assert or something like that.
| @@ -278,6 +278,44 @@ constantFoldBinaryWithOverflow(BuiltinInst *BI, BuiltinValueKind ID, | |||
| ResultsInError); | |||
| } | |||
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| static SILValue countZeros(BuiltinInst *BI, llvm::Intrinsic::ID ID) { | |||
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I find this name means nothing and this needs a comment. My suggestion:
/// Constant fold a cttz or ctlz builtin inst of an integer literal. If \p countLeadingZeros is set to true, then we
/// assume \p bi must be ctlz. If false, \p bi must be cttz.
///
/// NOTE: We assert that \p bi is either cttz or ctlz.
static SILValue constantFoldCountLeadingOrTrialingZeroIntrinsic(BuiltinInst *bi, bool countLeadingZeros) {
...
}
/// Count either the leading or trailing zeros.
Also, do you really need the intrinsic id here? Couldn't you just pass in a bool stating which of the two you are handling?
| @@ -278,6 +278,44 @@ constantFoldBinaryWithOverflow(BuiltinInst *BI, BuiltinValueKind ID, | |||
| ResultsInError); | |||
| } | |||
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| static SILValue countZeros(BuiltinInst *BI, llvm::Intrinsic::ID ID) { | |||
| assert(BI->getArguments().size() == 2 && "Ctlz should have 2 args."); | |||
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This is a bad assert message. You are handling both ctlz and cttz.
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Another thing. You can make all of this much simpler by using PatternMatch.h. |
rdar://problem/29522851