@llvm.sqrt isn't really close enough to C's sqrt to justify emitting calls
to the intrinsic, even when math-errno is off.
Fixes rdar://problem/7828230 by falling back on the library function.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@100613 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 38c40ed..a46cc39 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -682,13 +682,12 @@
case Builtin::BIsqrt:
case Builtin::BIsqrtf:
case Builtin::BIsqrtl: {
- // Rewrite sqrt to intrinsic if allowed.
- if (!FD->hasAttr<ConstAttr>())
- break;
- Value *Arg0 = EmitScalarExpr(E->getArg(0));
- const llvm::Type *ArgType = Arg0->getType();
- Value *F = CGM.getIntrinsic(Intrinsic::sqrt, &ArgType, 1);
- return RValue::get(Builder.CreateCall(F, Arg0, "tmp"));
+ // 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;
}
case Builtin::BIpow: