diff --git a/builtins.cpp b/builtins.cpp
index 57ce2333..69559b51 100644
--- a/builtins.cpp
+++ b/builtins.cpp
@@ -725,7 +725,7 @@ lDefineConstantIntFunc(const char *name, int val, llvm::Module *module,
     Assert(func != NULL); // it should be declared already...
 #if defined(LLVM_3_2)
     func->addFnAttr(llvm::Attributes::AlwaysInline);
-#else
+#else // LLVM 3.1 and 3.3+
     func->addFnAttr(llvm::Attribute::AlwaysInline);
 #endif
     llvm::BasicBlock *bblock = llvm::BasicBlock::Create(*g->ctx, "entry", func, 0);
diff --git a/cbackend.cpp b/cbackend.cpp
index 45cc29f9..d335d4e9 100644
--- a/cbackend.cpp
+++ b/cbackend.cpp
@@ -88,10 +88,10 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
-#if defined(LLVM_3_3)
-  #include "llvm/InstVisitor.h"
-#else
+#if defined(LLVM_3_1) || defined(LLVM_3_2)
   #include "llvm/Support/InstVisitor.h"
+#else // LLVM 3.3+
+  #include "llvm/InstVisitor.h"
 #endif
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/TargetRegistry.h"
diff --git a/ctx.cpp b/ctx.cpp
index 1119f819..9f7c3bfb 100644
--- a/ctx.cpp
+++ b/ctx.cpp
@@ -3293,7 +3293,7 @@ FunctionEmitContext::CallInst(llvm::Value *func, const FunctionType *funcType,
         // alias analysis.
         // TODO: what other attributes needs to be copied?
         // TODO: do the same for varing path.
-#if defined (LLVM_3_3)
+#if !defined (LLVM_3_1) && !defined (LLVM_3_2) // LLVM 3.3+
         llvm::CallInst *cc = llvm::dyn_cast<llvm::CallInst>(ci);
         if (cc &&
             cc->getCalledFunction() &&
diff --git a/ispc.cpp b/ispc.cpp
index daa3f5a8..40bf0020 100644
--- a/ispc.cpp
+++ b/ispc.cpp
@@ -138,9 +138,9 @@ lGetSystemISA() {
 
 static const char *supportedCPUs[] = {
     "atom", "penryn", "core2", "corei7", "corei7-avx"
-#if defined(LLVM_3_2) || defined(LLVM_3_3)
+#if !defined(LLVM_3_1)
     , "core-avx-i", "core-avx2"
-#endif // LLVM_3_2 or LLVM_3_3
+#endif // LLVM 3.2+
 };
 
 Target::Target(const char *arch, const char *cpu, const char *isa, bool pic) :
diff --git a/ispc.h b/ispc.h
index 8b385bf6..3582e2fc 100644
--- a/ispc.h
+++ b/ispc.h
@@ -40,8 +40,8 @@
 
 #define ISPC_VERSION "1.3.1dev"
 
-#if !defined(LLVM_3_1) && !defined(LLVM_3_2) && !defined(LLVM_3_3)
-#error "Only LLVM 3.1, 3.2 and the 3.3 development branch are supported"
+#if !defined(LLVM_3_1) && !defined(LLVM_3_2) && !defined(LLVM_3_3) && !defined(LLVM_3_4)
+#error "Only LLVM 3.1, 3.2, 3.3 and the 3.4 development branch are supported"
 #endif
 
 #if defined(_WIN32) || defined(_WIN64)
diff --git a/main.cpp b/main.cpp
index d58ff71d..cc005fde 100644
--- a/main.cpp
+++ b/main.cpp
@@ -68,6 +68,8 @@ lPrintVersion() {
            "3.2"
 #elif defined(LLVM_3_3)
            "3.3"
+#elif defined(LLVM_3_4)
+           "3.4"
 #else
 #error "Unhandled LLVM version"
 #endif
diff --git a/module.cpp b/module.cpp
index 910a3f27..ad672672 100644
--- a/module.cpp
+++ b/module.cpp
@@ -88,14 +88,12 @@
 #include <llvm/Target/TargetOptions.h>
 #if defined(LLVM_3_1)
   #include <llvm/Target/TargetData.h>
-#else
-  #if defined(LLVM_3_2)
-    #include <llvm/DataLayout.h>
-    #include <llvm/TargetTransformInfo.h>
-  #else // LLVM 3.3+
-    #include <llvm/IR/DataLayout.h>
-    #include <llvm/Analysis/TargetTransformInfo.h>
-  #endif
+#elif defined(LLVM_3_2)
+  #include <llvm/DataLayout.h>
+  #include <llvm/TargetTransformInfo.h>
+#else // LLVM 3.3+
+  #include <llvm/IR/DataLayout.h>
+  #include <llvm/Analysis/TargetTransformInfo.h>
 #endif
 #include <llvm/Analysis/Verifier.h>
 #include <llvm/Support/CFG.h>
@@ -768,14 +766,14 @@ Module::AddFunctionDeclaration(const std::string &name,
         isInline)
 #ifdef LLVM_3_2
         function->addFnAttr(llvm::Attributes::AlwaysInline);
-#else
+#else // LLVM 3.1 and 3.3+
         function->addFnAttr(llvm::Attribute::AlwaysInline);
 #endif
     if (functionType->isTask)
         // This also applies transitively to members I think?
 #if defined(LLVM_3_1)
         function->setDoesNotAlias(1, true);
-#else
+#else // LLVM 3.2+
         function->setDoesNotAlias(1);
 #endif
 
@@ -1817,7 +1815,7 @@ Module::execPreprocessor(const char *infilename, llvm::raw_string_ostream *ostre
     // track the source file position by handling them ourselves.
     inst.getPreprocessorOutputOpts().ShowComments = 1;
 
-#if defined(LLVM_3_3)
+#if !defined(LLVM_3_1) && !defined(LLVM_3_2) // LLVM 3.3+
     inst.getPreprocessorOutputOpts().ShowCPP = 1;
 #endif
 
@@ -1829,7 +1827,7 @@ Module::execPreprocessor(const char *infilename, llvm::raw_string_ostream *ostre
         headerOpts.Verbose = 1;
     for (int i = 0; i < (int)g->includePath.size(); ++i) {
         headerOpts.AddPath(g->includePath[i], clang::frontend::Angled,
-#if !defined(LLVM_3_3)
+#if defined(LLVM_3_1) || defined(LLVM_3_2)
                            true /* is user supplied */,
 #endif
                            false /* not a framework */,