From 93964525922f5b13cbc3b0a28175082acf50f587 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Wed, 5 Mar 2014 15:14:16 -0800
Subject: [PATCH] rustc: Fix support for LLVM 3.3

The llvm.copysign and llvm.round intrinsics weren't added until LLVM 3.4, so if
we're on LLVM 3.3 we lower these to calls in libm instead of LLVM intrinsics.

This should fix our travis failures.
---
 src/librustc/lib/llvm.rs          |  1 +
 src/librustc/middle/trans/base.rs | 30 ++++++++++++++++++++++++++----
 src/rustllvm/RustWrapper.cpp      |  5 +++++
 3 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/librustc/lib/llvm.rs b/src/librustc/lib/llvm.rs
index bea08366db3..448b9e30dcd 100644
--- a/src/librustc/lib/llvm.rs
+++ b/src/librustc/lib/llvm.rs
@@ -1771,6 +1771,7 @@ pub fn LLVMRustArchiveReadSection(AR: ArchiveRef, name: *c_char,
         pub fn LLVMRustDestroyArchive(AR: ArchiveRef);
 
         pub fn LLVMRustSetDLLExportStorageClass(V: ValueRef);
+        pub fn LLVMVersionMinor() -> c_int;
     }
 }
 
diff --git a/src/librustc/middle/trans/base.rs b/src/librustc/middle/trans/base.rs
index f838bcf9c5e..bd4ef16d19d 100644
--- a/src/librustc/middle/trans/base.rs
+++ b/src/librustc/middle/trans/base.rs
@@ -2286,8 +2286,6 @@ pub fn declare_intrinsics(llmod: ModuleRef) -> HashMap<&'static str, ValueRef> {
 
     ifn!(intrinsics, "llvm.fabs.f32", [Type::f32()], Type::f32());
     ifn!(intrinsics, "llvm.fabs.f64", [Type::f64()], Type::f64());
-    ifn!(intrinsics, "llvm.copysign.f32", [Type::f32(), Type::f32()], Type::f32());
-    ifn!(intrinsics, "llvm.copysign.f64", [Type::f64(), Type::f64()], Type::f64());
 
     ifn!(intrinsics, "llvm.floor.f32",[Type::f32()], Type::f32());
     ifn!(intrinsics, "llvm.floor.f64",[Type::f64()], Type::f64());
@@ -2300,8 +2298,6 @@ pub fn declare_intrinsics(llmod: ModuleRef) -> HashMap<&'static str, ValueRef> {
     ifn!(intrinsics, "llvm.rint.f64", [Type::f64()], Type::f64());
     ifn!(intrinsics, "llvm.nearbyint.f32", [Type::f32()], Type::f32());
     ifn!(intrinsics, "llvm.nearbyint.f64", [Type::f64()], Type::f64());
-    ifn!(intrinsics, "llvm.round.f32", [Type::f32()], Type::f32());
-    ifn!(intrinsics, "llvm.round.f64", [Type::f64()], Type::f64());
 
     ifn!(intrinsics, "llvm.ctpop.i8", [Type::i8()], Type::i8());
     ifn!(intrinsics, "llvm.ctpop.i16",[Type::i16()], Type::i16());
@@ -2378,6 +2374,32 @@ pub fn declare_intrinsics(llmod: ModuleRef) -> HashMap<&'static str, ValueRef> {
 
     ifn!(intrinsics, "llvm.expect.i1", [Type::i1(), Type::i1()], Type::i1());
 
+    // Some intrinsics were introduced in later versions of LLVM, but they have
+    // fallbacks in libc or libm and such. Currently, all of these intrinsics
+    // were introduced in LLVM 3.4, so we case on that.
+    macro_rules! compatible_ifn (
+        ($intrinsics:ident, $name:expr, $cname:expr, $args:expr, $ret:expr) => ({
+            let name = $name;
+            if unsafe { llvm::LLVMVersionMinor() >= 4 } {
+                ifn!($intrinsics, $name, $args, $ret);
+            } else {
+                let f = decl_cdecl_fn(llmod, $cname,
+                                      Type::func($args, &$ret),
+                                      ty::mk_nil());
+                $intrinsics.insert(name, f);
+            }
+        })
+    )
+
+    compatible_ifn!(intrinsics, "llvm.copysign.f32", "copysignf",
+                    [Type::f32(), Type::f32()], Type::f32());
+    compatible_ifn!(intrinsics, "llvm.copysign.f64", "copysign",
+                    [Type::f64(), Type::f64()], Type::f64());
+    compatible_ifn!(intrinsics, "llvm.round.f32", "roundf",
+                    [Type::f32()], Type::f32());
+    compatible_ifn!(intrinsics, "llvm.round.f64", "round",
+                    [Type::f64()], Type::f64());
+
     return intrinsics;
 }
 
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index d8fc5b15850..aaaf512bcf3 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -652,3 +652,8 @@ LLVMRustSetDLLExportStorageClass(LLVMValueRef Value) {
     LLVMSetLinkage(Value, LLVMDLLExportLinkage);
 }
 #endif
+
+extern "C" int
+LLVMVersionMinor() {
+    return LLVM_VERSION_MINOR;
+}
-- 
2.44.0