1 files changed, 18 insertions, 14 deletions
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 962f5d8a517..6324520350b 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -854,12 +854,11 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
                                                Result.Val.getFloat()));
   }
 
-  // Math builtins have the same semantics as their math library twins.
-  // There are LLVM math intrinsics corresponding to math library functions
-  // except the intrinsic will never set errno while the math library might.
-  // Thus, we can transform math library and builtin calls to their
-  // semantically-equivalent LLVM intrinsic counterparts if the call is marked
-  // 'const' (it is known to never set errno).
+  // There are LLVM math intrinsics/instructions corresponding to math library
+  // functions except the LLVM op will never set errno while the math library
+  // might. Also, math builtins have the same semantics as their math library
+  // twins. Thus, we can transform math library and builtin calls to their
+  // LLVM counterparts if the call is marked 'const' (known to never set errno).
   if (FD->hasAttr<ConstAttr>()) {
     switch (BuiltinID) {
     case Builtin::BIceil:
@@ -942,6 +941,19 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     case Builtin::BI__builtin_fminl:
       return RValue::get(emitBinaryBuiltin(*this, E, Intrinsic::minnum));
 
+    // fmod() is a special-case. It maps to the frem instruction rather than an
+    // LLVM intrinsic.
+    case Builtin::BIfmod:
+    case Builtin::BIfmodf:
+    case Builtin::BIfmodl:
+    case Builtin::BI__builtin_fmod:
+    case Builtin::BI__builtin_fmodf:
+    case Builtin::BI__builtin_fmodl: {
+      Value *Arg1 = EmitScalarExpr(E->getArg(0));
+      Value *Arg2 = EmitScalarExpr(E->getArg(1));
+      return RValue::get(Builder.CreateFRem(Arg1, Arg2, "fmod"));
+    }
+
     case Builtin::BIlog:
     case Builtin::BIlogf:
     case Builtin::BIlogl:
@@ -1067,14 +1079,6 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
 
     return RValue::get(Result);
   }
-  case Builtin::BI__builtin_fmod:
-  case Builtin::BI__builtin_fmodf:
-  case Builtin::BI__builtin_fmodl: {
-    Value *Arg1 = EmitScalarExpr(E->getArg(0));
-    Value *Arg2 = EmitScalarExpr(E->getArg(1));
-    Value *Result = Builder.CreateFRem(Arg1, Arg2, "fmod");
-    return RValue::get(Result);
-  }
   case Builtin::BI__builtin_conj:
   case Builtin::BI__builtin_conjf:
   case Builtin::BI__builtin_conjl: {