rustc_trans: work around i686-pc-windows-msvc byval align LLVM bug.

Author: eddyb

src/librustc_trans/abi.rs

@@ -491,7 +491,9 @@ impl<'a, 'tcx> ArgType<'tcx> {
              .set(ArgAttribute::NoCapture)
              .set(ArgAttribute::NonNull);
         attrs.pointee_size = self.layout.size;
-        attrs.pointee_align = Some(self.layout.align);
+        // FIXME(eddyb) We should be doing this, but at least on
+        // i686-pc-windows-msvc, it results in wrong stack offsets.
+        // attrs.pointee_align = Some(self.layout.align);
 
         self.mode = PassMode::Indirect(attrs);
     }

src/test/codegen/function-arguments.rs

@@ -66,7 +66,7 @@ pub fn mutable_unsafe_borrow(_: &mut UnsafeInner) {
 pub fn mutable_borrow(_: &mut i32) {
 }
 
-// CHECK: @indirect_struct(%S* noalias nocapture align 4 dereferenceable(32) %arg0)
+// CHECK: @indirect_struct(%S* noalias nocapture dereferenceable(32) %arg0)
 #[no_mangle]
 pub fn indirect_struct(_: S) {
 }
@@ -83,7 +83,7 @@ pub fn _box(x: Box<i32>) -> Box<i32> {
   x
 }
 
-// CHECK: @struct_return(%S* noalias nocapture sret align 4 dereferenceable(32))
+// CHECK: @struct_return(%S* noalias nocapture sret dereferenceable(32))
 #[no_mangle]
 pub fn struct_return() -> S {
   S {

src/test/codegen/packed.rs

@@ -39,7 +39,7 @@ pub struct BigPacked {
 #[no_mangle]
 pub fn call_pkd(f: fn() -> Array) -> BigPacked {
 // CHECK: [[ALLOCA:%[_a-z0-9]+]] = alloca %Array
-// CHECK: call void %{{.*}}(%Array* noalias nocapture sret align 4 dereferenceable(32) [[ALLOCA]])
+// CHECK: call void %{{.*}}(%Array* noalias nocapture sret dereferenceable(32) [[ALLOCA]])
 // CHECK: call void @llvm.memcpy.{{.*}}(i8* %{{.*}}, i8* %{{.*}}, i{{[0-9]+}} 32, i32 1, i1 false)
     // check that calls whose destination is a field of a packed struct
     // go through an alloca rather than calling the function with an