[PATCH] Re-enable movw/movt on iOS static platforms

[Tim Northover]

Hi all (well, mostly Apple people),

There's a bit of code to generate movw/movt for static Darwin targets
that's been dead in ARMISelLowering since 2011, and I think it's time
we did something about it.

Apparently some tools didn't like the static movw/movt relocations,
but I believe those issues are now no longer relevant
(rdar://problem/9514789). For uniformity I'd quite like to re-enable
it, though removing it completely is another option.

The patch re-enables it.

OK to commit?

Cheers.

Tim.
-------------- next part --------------
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index a4004f3..271b9d4 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -683,7 +683,7 @@ unsigned ARMFastISel::ARMMaterializeGV(const GlobalValue *GV, MVT VT) {
   // ARMTargetLowering::LowerGlobalAddressDarwin.  Other targets only support
   // static movt relocations.
   if (Subtarget->useMovt() &&
-      Subtarget->isTargetDarwin() == (RelocM != Reloc::Static)) {
+      (Subtarget->isTargetDarwin() || RelocM == Reloc::Static)) {
     unsigned Opc;
     switch (RelocM) {
     case Reloc::PIC_:
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 76a0a83..689187e 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -2540,7 +2540,7 @@ SDValue ARMTargetLowering::LowerGlobalAddressDarwin(SDValue Op,
 
   // FIXME: Enable this for static codegen when tool issues are fixed.  Also
   // update ARMFastISel::ARMMaterializeGV.
-  if (Subtarget->useMovt() && RelocM != Reloc::Static) {
+  if (Subtarget->useMovt()) {
     ++NumMovwMovt;
     // FIXME: Once remat is capable of dealing with instructions with register
     // operands, expand this into two nodes.
diff --git a/test/CodeGen/ARM/movt-movw-global.ll b/test/CodeGen/ARM/movt-movw-global.ll
index bbedea1..1e10af1 100644
--- a/test/CodeGen/ARM/movt-movw-global.ll
+++ b/test/CodeGen/ARM/movt-movw-global.ll
@@ -16,8 +16,8 @@ entry:
 ; IOS-PIC:      movw    r0, :lower16:(L_foo$non_lazy_ptr-(LPC0_0+8))
 ; IOS-PIC-NEXT: movt    r0, :upper16:(L_foo$non_lazy_ptr-(LPC0_0+8))
 
-; IOS-STATIC-NOT:      movw    r0, :lower16:_foo
-; IOS-STATIC-NOT:       movt    r0, :upper16:_foo
+; IOS-STATIC:      movw    r0, :lower16:_foo
+; IOS-STATIC-NEXT:       movt    r0, :upper16:_foo
   ret i32* @foo
 }
 
@@ -32,8 +32,8 @@ entry:
 ; IOS-PIC:      movw    r1, :lower16:(L_foo$non_lazy_ptr-(LPC1_0+8))
 ; IOS-PIC-NEXT: movt    r1, :upper16:(L_foo$non_lazy_ptr-(LPC1_0+8))
 
-; IOS-STATIC-NOT:      movw    r1, :lower16:_foo
-; IOS-STATIC-NOT:      movt    r1, :upper16:_foo
+; IOS-STATIC:      movw    r1, :lower16:_foo
+; IOS-STATIC-NEXT:      movt    r1, :upper16:_foo
   store i32 %baz, i32* @foo, align 4
   ret void
 }