PR3589: Don't simplify libcalls with -ffreestanding.

llvm-svn: 64599

2 files changed, 10 insertions, 1 deletions

diff --git a/clang/Driver/clang.cpp b/clang/Driver/clang.cpp
index 2f7ce69ee39..d1ef871d6a1 100644
--- a/clang/Driver/clang.cpp
+++ b/clang/Driver/clang.cpp
@@ -1271,7 +1271,7 @@ static void InitializeCompileOptions(CompileOptions &Opts) {
   // FIXME: There are llvm-gcc options to control these selectively.
   Opts.InlineFunctions = (Opts.OptimizationLevel > 1);
   Opts.UnrollLoops = (Opts.OptimizationLevel > 1 && !OptSize);
-  Opts.SimplifyLibCalls = 1;
+  Opts.SimplifyLibCalls = !Freestanding;
 
 #ifdef NDEBUG
   Opts.VerifyModule = 0;
diff --git a/clang/test/CodeGen/PR3589-freestanding-libcalls.c b/clang/test/CodeGen/PR3589-freestanding-libcalls.c
new file mode 100644
index 00000000000..61852e3c49b
--- /dev/null
+++ b/clang/test/CodeGen/PR3589-freestanding-libcalls.c
@@ -0,0 +1,9 @@
+// RUN: clang -emit-llvm %s -o - | grep 'declare i32 @printf' | count 1 &&
+// RUN: clang -O2 -emit-llvm %s -o - | grep 'declare i32 @puts' | count 1 &&
+// RUN: clang -ffreestanding -O2 -emit-llvm %s -o - | grep 'declare i32 @puts' | count 0
+
+#include <stdio.h>
+
+void f0() {
+  printf("hello\n");
+}