From 2af5035a1d4124881c8fe3d46354341d01374fb7 Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Mon, 18 Feb 2013 23:17:16 +0000
Subject: Check to see if the 'no-builtin' attribute is set before simplifying
 a library call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175470 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/SimplifyLibCalls.cpp |  3 +++
 test/Transforms/InstCombine/no-builtin.ll | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 test/Transforms/InstCombine/no-builtin.ll

diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index cccf0a6..2f47174 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1889,6 +1889,9 @@ LibCallSimplifier::~LibCallSimplifier() {
 }
 
 Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
+  Function *F = CI->getParent()->getParent();
+  // We don't want to "optimize" if the function doesn't want builtins.
+  if (F->hasFnAttribute("no-builtin")) return 0;
   return Impl->optimizeCall(CI);
 }
 
diff --git a/test/Transforms/InstCombine/no-builtin.ll b/test/Transforms/InstCombine/no-builtin.ll
new file mode 100644
index 0000000..a576cd4
--- /dev/null
+++ b/test/Transforms/InstCombine/no-builtin.ll
@@ -0,0 +1,23 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+@.str = private unnamed_addr constant [14 x i8] c"hello world!\0A\00", align 1
+
+; CHECK: @foo
+; CHECK: printf
+define void @foo() nounwind ssp uwtable "no-builtin" {
+entry:
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x i8]* @.str, i32 0, i32 0))
+  ret void
+}
+
+; CHECK: @bar
+; CHECK: puts
+define void @bar() nounwind ssp uwtable {
+entry:
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([14 x i8]* @.str, i32 0, i32 0))
+  ret void
+}
+
+declare i32 @printf(i8*, ...)
+
+attributes #0 = { nounwind ssp uwtable "no-builtin" }
+attributes #1 = { nounwind ssp uwtable }
-- 
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