From 68784efaf62af6cc4234ea01f378e859dd7bfbab Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 6 May 2010 05:50:07 +0000
Subject: [PATCH] optimize builtin_isnan/isinf to not do an extraneous
 extension from float -> double (which happens because they are modelled as
 int(...) functions), and add a testcase for isinf.

llvm-svn: 103167
---
 clang/lib/Sema/SemaChecking.cpp | 15 ++++++++++++++-
 clang/test/CodeGen/builtins.c   | 18 ++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 7029711d446c..e60dfd3452c7 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -607,12 +607,25 @@ bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
   if (OrigArg->isTypeDependent())
     return false;
 
-  // This operation requires a floating-point number
+  // This operation requires a non-_Complex floating-point number.
   if (!OrigArg->getType()->isRealFloatingType())
     return Diag(OrigArg->getLocStart(),
                 diag::err_typecheck_call_invalid_unary_fp)
       << OrigArg->getType() << OrigArg->getSourceRange();
 
+  // If this is an implicit conversion from float -> double, remove it.
+  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
+    Expr *CastArg = Cast->getSubExpr();
+    if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
+      assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
+             "promotion from float to double is the only expected cast here");
+      Cast->setSubExpr(0);
+      Cast->Destroy(Context);
+      TheCall->setArg(NumArgs-1, CastArg);
+      OrigArg = CastArg;
+    }
+  }
+  
   return false;
 }
 
diff --git a/clang/test/CodeGen/builtins.c b/clang/test/CodeGen/builtins.c
index a4424d77428f..e604fbe31893 100644
--- a/clang/test/CodeGen/builtins.c
+++ b/clang/test/CodeGen/builtins.c
@@ -163,3 +163,21 @@ void bar() {
 
 }
 // CHECK: }
+
+
+// CHECK: define void @test_inff
+void test_inff(float F, double D, long double LD) {
+  volatile int res;
+  res = __builtin_isinf(F);
+  // CHECK:  call float @fabsf(float
+  // CHECK:  fcmp oeq float {{.*}}, 0x7FF0000000000000
+
+  res = __builtin_isinf(D);
+  // CHECK:  call double @fabs(double
+  // CHECK:  fcmp oeq double {{.*}}, 0x7FF0000000000000
+  
+  res = __builtin_isinf(LD);
+  // CHECK:  call x86_fp80 @fabsl(x86_fp80
+  // CHECK:  fcmp oeq x86_fp80 {{.*}}, 0xK7FFF8000000000000000
+}
+