Fix memcmp code-gen to honor -fno-builtin.

I noticed that SelectionDAGBuilder::visitCall was missing a check for memcmp
in TargetLibraryInfo, so that it would use custom code for memcmp calls even
with -fno-builtin.  I also had to add a new -disable-simplify-libcalls option
to llc so that I could write a test for this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161262 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/tools/llc/llc.cpp b/tools/llc/llc.cpp
index 004763f19fa..8951050c07c 100644
--- a/tools/llc/llc.cpp
+++ b/tools/llc/llc.cpp
@@ -35,6 +35,7 @@
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include <memory>
 using namespace llvm;
@@ -214,6 +215,11 @@ DontPlaceZerosInBSS("nozero-initialized-in-bss",
   cl::init(false));
 
 static cl::opt<bool>
+DisableSimplifyLibCalls("disable-simplify-libcalls",
+  cl::desc("Disable simplify-libcalls"),
+  cl::init(false));
+
+static cl::opt<bool>
 EnableGuaranteedTailCallOpt("tailcallopt",
   cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
   cl::init(false));
@@ -487,6 +493,12 @@ int main(int argc, char **argv) {
   // Build up all of the passes that we want to do to the module.
   PassManager PM;
 
+  // Add an appropriate TargetLibraryInfo pass for the module's triple.
+  TargetLibraryInfo *TLI = new TargetLibraryInfo(TheTriple);
+  if (DisableSimplifyLibCalls)
+    TLI->disableAllFunctions();
+  PM.add(TLI);
+
   // Add the target data from the target machine, if it exists, or the module.
   if (const TargetData *TD = Target.getTargetData())
     PM.add(new TargetData(*TD));