From: Reid Kleckner <reid@kleckner.net>
Date: Mon, 3 Nov 2014 23:52:09 +0000 (+0000)
Subject: Lower __builtin_fabs* to @llvm.fabs.*
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=580ce364df0484cffd0189ac74714bf443953d49;p=clang

Lower __builtin_fabs* to @llvm.fabs.*

mingw64's headers implement fabs by calling __builtin_fabs, so using the
library call results in an infinite loop. If the backend legalizes
@llvm.fabs as a call to fabs later, things should work out, as the crt
provides a definition.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221206 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 0972e28069..aa11a906f4 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -245,6 +245,13 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
 
     return RValue::get(Result);
   }
+  case Builtin::BI__builtin_fabs:
+  case Builtin::BI__builtin_fabsf:
+  case Builtin::BI__builtin_fabsl: {
+    Value *Arg1 = EmitScalarExpr(E->getArg(0));
+    Value *Result = EmitFAbs(*this, Arg1);
+    return RValue::get(Result);
+  }
   case Builtin::BI__builtin_fmod:
   case Builtin::BI__builtin_fmodf:
   case Builtin::BI__builtin_fmodl: {
diff --git a/test/CodeGen/builtins.c b/test/CodeGen/builtins.c
index 6dd749a90b..1ab29a659b 100644
--- a/test/CodeGen/builtins.c
+++ b/test/CodeGen/builtins.c
@@ -211,6 +211,13 @@ void test_float_builtin_ops(float F, double D, long double LD) {
 
   resld = __builtin_fmodl(LD,LD);
   // CHECK: frem x86_fp80
+
+  resf = __builtin_fabsf(F);
+  resd = __builtin_fabs(D);
+  resld = __builtin_fabsl(LD);
+  // CHECK: call float @llvm.fabs.f32(float
+  // CHECK: call double @llvm.fabs.f64(double
+  // CHECK: call x86_fp80 @llvm.fabs.f80(x86_fp80
 }
 
 // CHECK-LABEL: define void @test_builtin_longjmp