[PATCH 1/1] CGBuiltin: Use frem instruction rather than libcall to implement fmod

[Jan Vesely]

AFAICT the semantics of frem match libm's fmod.

Signed-off-by: Jan Vesely <jan.vesely at rutgers.edu>
---
 lib/CodeGen/CGBuiltin.cpp |  8 ++++++++
 test/CodeGen/builtins.c   | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 69ad762..9238aae 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -241,6 +241,14 @@ 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:
diff --git a/test/CodeGen/builtins.c b/test/CodeGen/builtins.c
index 451ed07..6dd749a 100644
--- a/test/CodeGen/builtins.c
+++ b/test/CodeGen/builtins.c
@@ -197,6 +197,22 @@ void test_float_builtins(float F, double D, long double LD) {
   // CHECK: and i1
 }
 
+// CHECK-LABEL: define void @test_float_builtin_ops
+void test_float_builtin_ops(float F, double D, long double LD) {
+  volatile float resf;
+  volatile double resd;
+  volatile long double resld;
+
+  resf = __builtin_fmodf(F,F);
+  // CHECK: frem float
+
+  resd = __builtin_fmod(D,D);
+  // CHECK: frem double
+
+  resld = __builtin_fmodl(LD,LD);
+  // CHECK: frem x86_fp80
+}
+
 // CHECK-LABEL: define void @test_builtin_longjmp
 void test_builtin_longjmp(void **buffer) {
   // CHECK: [[BITCAST:%.*]] = bitcast
-- 
1.9.3