Merge branch 'master' into mb/36812_ICHFunctionInterfaces

Author: Mathieu Borderé

src/librustc_mir/build/expr/as_lvalue.rs

@@ -96,6 +96,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ExprKind::LogicalOp { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::NeverToAny { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |

src/librustc_mir/build/expr/as_rvalue.rs

@@ -115,6 +115,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 let source = unpack!(block = this.as_operand(block, source));
                 block.and(Rvalue::Cast(CastKind::Misc, source, expr.ty))
             }
+            ExprKind::Use { source } => {
+                let source = unpack!(block = this.as_operand(block, source));
+                block.and(Rvalue::Use(source))
+            }
             ExprKind::ReifyFnPointer { source } => {
                 let source = unpack!(block = this.as_operand(block, source));
                 block.and(Rvalue::Cast(CastKind::ReifyFnPointer, source, expr.ty))

src/librustc_mir/build/expr/category.rs

@@ -68,6 +68,7 @@ impl Category {
             ExprKind::Binary { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |
             ExprKind::Unsize { .. } |

src/librustc_mir/build/expr/into.rs

@@ -249,6 +249,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             ExprKind::Binary { .. } |
             ExprKind::Box { .. } |
             ExprKind::Cast { .. } |
+            ExprKind::Use { .. } |
             ExprKind::ReifyFnPointer { .. } |
             ExprKind::UnsafeFnPointer { .. } |
             ExprKind::Unsize { .. } |

src/librustc_mir/hair/cx/expr.rs

@@ -600,8 +600,8 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             // Check to see if this cast is a "coercion cast", where the cast is actually done
             // using a coercion (or is a no-op).
             if let Some(&TyCastKind::CoercionCast) = cx.tcx.cast_kinds.borrow().get(&source.id) {
-                // Skip the actual cast itexpr, as it's now a no-op.
-                return source.make_mirror(cx);
+                // Convert the lexpr to a vexpr.
+                ExprKind::Use { source: source.to_ref() }
             } else {
                 ExprKind::Cast { source: source.to_ref() }
             }

src/librustc_mir/hair/mod.rs

@@ -139,6 +139,9 @@ pub enum ExprKind<'tcx> {
     Cast {
         source: ExprRef<'tcx>,
     },
+    Use {
+        source: ExprRef<'tcx>,
+    }, // Use a lexpr to get a vexpr.
     NeverToAny {
         source: ExprRef<'tcx>,
     },

src/librustc_trans/base.rs

@@ -308,7 +308,16 @@ pub fn compare_scalar_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
                 _ => bug!("compare_scalar_types: must be a comparison operator"),
             }
         }
-        ty::TyFnDef(..) | ty::TyFnPtr(_) | ty::TyBool | ty::TyUint(_) | ty::TyChar => {
+        ty::TyBool => {
+            // FIXME(#36856) -- using `from_immediate` forces these booleans into `i8`,
+            // which works around some LLVM bugs
+            ICmp(bcx,
+                 bin_op_to_icmp_predicate(op, false),
+                 from_immediate(bcx, lhs),
+                 from_immediate(bcx, rhs),
+                 debug_loc)
+        }
+        ty::TyFnDef(..) | ty::TyFnPtr(_) | ty::TyUint(_) | ty::TyChar => {
             ICmp(bcx,
                  bin_op_to_icmp_predicate(op, false),
                  lhs,