diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index bdd310e..3fc1357 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -17,6 +17,7 @@ #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/MemoryBuiltins.h" #include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetLibraryInfo.h" #include "llvm/Support/ConstantRange.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/PatternMatch.h" @@ -2985,6 +2986,44 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) { return Res; } break; + case Instruction::Call: { + CallInst *CI = cast<CallInst>(LHSI); + LibFunc::Func Func; + // Various optimization for fabs compared with zero. + if (RHSC->isNullValue() && CI->hasOneUse() && + TLI->getLibFunc(CI->getCalledFunction()->getName(), Func) && + TLI->has(Func)) { + if (Func == LibFunc::fabs || Func == LibFunc::fabsf || + Func == LibFunc::fabsl) { + switch (I.getPredicate()) { + default: break; + // fabs(x) < 0 --> false + case FCmpInst::FCMP_OLT: + return ReplaceInstUsesWith(I, Builder->getFalse()); + // fabs(x) > 0 --> x != 0 + case FCmpInst::FCMP_OGT: + return new FCmpInst(FCmpInst::FCMP_ONE, CI->getArgOperand(0), + RHSC); + // fabs(x) <= 0 --> x == 0 + case FCmpInst::FCMP_OLE: + return new FCmpInst(FCmpInst::FCMP_OEQ, CI->getArgOperand(0), + RHSC); + // fabs(x) >= 0 --> !isnan(x) + case FCmpInst::FCMP_OGE: + return new FCmpInst(FCmpInst::FCMP_ORD, CI->getArgOperand(0), + RHSC); + // fabs(x) == 0 --> x == 0 + // fabs(x) != 0 --> x != 0 + case FCmpInst::FCMP_OEQ: + case FCmpInst::FCMP_UEQ: + case FCmpInst::FCMP_ONE: + case FCmpInst::FCMP_UNE: + return new FCmpInst(I.getPredicate(), CI->getArgOperand(0), + RHSC); + } + } + } + } } } |