rustc_codegen_llvm: don't overalign loads of pair operands.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/librustc_codegen_llvm/builder.rs b/src/librustc_codegen_llvm/builder.rs
index d2a99eae340..f6bc348b8dc 100644
--- a/src/librustc_codegen_llvm/builder.rs
+++ b/src/librustc_codegen_llvm/builder.rs
@@ -589,9 +589,11 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
             });
             OperandValue::Immediate(to_immediate(self, llval, place.layout))
         } else if let layout::Abi::ScalarPair(ref a, ref b) = place.layout.abi {
-            let mut load = |i, scalar: &layout::Scalar| {
+            let b_offset = a.value.size(self).align_to(b.value.align(self).abi);
+
+            let mut load = |i, scalar: &layout::Scalar, align| {
                 let llptr = self.struct_gep(place.llval, i as u64);
-                let load = self.load(llptr, place.align);
+                let load = self.load(llptr, align);
                 scalar_load_metadata(self, load, scalar);
                 if scalar.is_bool() {
                     self.trunc(load, self.cx().type_i1())
@@ -599,7 +601,11 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                     load
                 }
             };
-            OperandValue::Pair(load(0, a), load(1, b))
+
+            OperandValue::Pair(
+                load(0, a, place.align),
+                load(1, b, place.align.restrict_for_offset(b_offset)),
+            )
         } else {
             OperandValue::Ref(place.llval, None, place.align)
         };