diff options
Diffstat (limited to 'clang/lib/CodeGen')
| -rw-r--r-- | clang/lib/CodeGen/CGBuiltin.cpp | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp index 5b5b39f5e34..e6cfe64471e 100644 --- a/clang/lib/CodeGen/CGBuiltin.cpp +++ b/clang/lib/CodeGen/CGBuiltin.cpp @@ -1282,12 +1282,19 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD, case Builtin::BIsqrt: case Builtin::BIsqrtf: case Builtin::BIsqrtl: { - // TODO: there is currently no set of optimizer flags - // sufficient for us to rewrite sqrt to @llvm.sqrt. - // -fmath-errno=0 is not good enough; we need finiteness. - // We could probably precondition the call with an ult - // against 0, but is that worth the complexity? - break; + // Transform a call to sqrt* into a @llvm.sqrt.* intrinsic call, but only + // in finite- or unsafe-math mode (the intrinsic has different semantics + // for handling negative numbers compared to the library function, so + // -fmath-errno=0 is not enough). + if (!FD->hasAttr<ConstAttr>()) + break; + if (!(CGM.getCodeGenOpts().UnsafeFPMath || + CGM.getCodeGenOpts().NoNaNsFPMath)) + break; + Value *Arg0 = EmitScalarExpr(E->getArg(0)); + llvm::Type *ArgType = Arg0->getType(); + Value *F = CGM.getIntrinsic(Intrinsic::sqrt, ArgType); + return RValue::get(Builder.CreateCall(F, Arg0)); } case Builtin::BIpow: |
