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lower calls to abs to inline code, PR2337

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llvm-svn: 52138
This commit is contained in:
Chris Lattner 2008-06-09 08:26:51 +00:00
parent 7864575654
commit 806f0a8411
2 changed files with 37 additions and 1 deletions
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27
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@ -984,6 +984,27 @@ struct VISIBILITY_HIDDEN IsAsciiOpt : public LibCallOptimization {
return B.CreateZExt(Op, CI->getType());
}
};
//===---------------------------------------===//
// 'abs', 'labs', 'llabs' Optimizations
struct VISIBILITY_HIDDEN AbsOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
const FunctionType *FT = Callee->getFunctionType();
// We require integer(integer) where the types agree.
if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
FT->getParamType(0) != FT->getReturnType())
return 0;
// abs(x) -> x >s -1 ? x : -x
Value *Op = CI->getOperand(1);
Value *Pos = B.CreateICmpSGT(Op,ConstantInt::getAllOnesValue(Op->getType()),
"ispos");
Value *Neg = B.CreateNeg(Op, "neg");
return B.CreateSelect(Pos, Op, Neg);
}
};
//===---------------------------------------===//
// 'toascii' Optimizations
@ -1258,7 +1279,8 @@ namespace {
// Math Library Optimizations
PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
// Integer Optimizations
FFSOpt FFS; IsDigitOpt IsDigit; IsAsciiOpt IsAscii; ToAsciiOpt ToAscii;
FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
ToAsciiOpt ToAscii;
// Formatting and IO Optimizations
SPrintFOpt SPrintF; PrintFOpt PrintF;
FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
@ -1328,6 +1350,9 @@ void SimplifyLibCalls::InitOptimizations() {
Optimizations["ffs"] = &FFS;
Optimizations["ffsl"] = &FFS;
Optimizations["ffsll"] = &FFS;
Optimizations["abs"] = &Abs;
Optimizations["labs"] = &Abs;
Optimizations["llabs"] = &Abs;
Optimizations["isdigit"] = &IsDigit;
Optimizations["isascii"] = &IsAscii;
Optimizations["toascii"] = &ToAscii;

11
test/Transforms/SimplifyLibCalls/abs.ll Normal file
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@ -0,0 +1,11 @@
; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | grep {select i1 %ispos}
; PR2337
define i32 @test(i32 %x) {
entry:
%call = call i32 @abs( i32 %x ) ; <i32> [#uses=1]
ret i32 %call
}
declare i32 @abs(i32)