codegen_llvm: improve common patterns

8 files changed, 86 insertions, 115 deletions

diff --git a/src/librustc_codegen_llvm/abi.rs b/src/librustc_codegen_llvm/abi.rs
index 1b007a6d814..1a1aeff3745 100644
--- a/src/librustc_codegen_llvm/abi.rs
+++ b/src/librustc_codegen_llvm/abi.rs
@@ -695,14 +695,13 @@ impl<'tcx> FnTypeExt<'tcx> for FnType<'tcx, Ty<'tcx>> {
             // If the value is a boolean, the range is 0..2 and that ultimately
             // become 0..0 when the type becomes i1, which would be rejected
             // by the LLVM verifier.
-            match scalar.value {
-                layout::Int(..) if !scalar.is_bool() => {
+            if let layout::Int(..) = scalar.value {
+                if !scalar.is_bool() {
                     let range = scalar.valid_range_exclusive(bx.cx);
                     if range.start != range.end {
                         bx.range_metadata(callsite, range);
                     }
                 }
-                _ => {}
             }
         }
         for arg in &self.args {
diff --git a/src/librustc_codegen_llvm/attributes.rs b/src/librustc_codegen_llvm/attributes.rs
index 89fe6911041..0abc26d6cfb 100644
--- a/src/librustc_codegen_llvm/attributes.rs
+++ b/src/librustc_codegen_llvm/attributes.rs
@@ -94,9 +94,8 @@ pub fn set_probestack(cx: &CodegenCx<'ll, '_>, llfn: &'ll Value) {
     // Currently stack probes seem somewhat incompatible with the address
     // sanitizer. With asan we're already protected from stack overflow anyway
     // so we don't really need stack probes regardless.
-    match cx.sess().opts.debugging_opts.sanitizer {
-        Some(Sanitizer::Address) => return,
-        _ => {}
+    if let Some(Sanitizer::Address) = cx.sess().opts.debugging_opts.sanitizer {
+        return
     }
 
     // probestack doesn't play nice either with pgo-gen.
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index a86865bdec4..0c2a423a18f 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -495,10 +495,8 @@ pub fn codegen_instance<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>, instance: Instance<'
     let sig = common::ty_fn_sig(cx, fn_ty);
     let sig = cx.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
 
-    let lldecl = match cx.instances.borrow().get(&instance) {
-        Some(&val) => val,
-        None => bug!("Instance `{:?}` not already declared", instance)
-    };
+    let lldecl = cx.instances.borrow().get(&instance).cloned().unwrap_or_else(||
+        bug!("Instance `{:?}` not already declared", instance));
 
     cx.stats.borrow_mut().n_closures += 1;
 
@@ -836,12 +834,7 @@ pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         .iter()
         .any(|(_, list)| {
             use rustc::middle::dependency_format::Linkage;
-            list.iter().any(|linkage| {
-                match linkage {
-                    Linkage::Dynamic => true,
-                    _ => false,
-                }
-            })
+            list.iter().any(|&linkage| linkage == Linkage::Dynamic)
         });
     let allocator_module = if any_dynamic_crate {
         None
diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index 53bb02ddd99..c08937fa9b9 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -336,16 +336,13 @@ pub fn langcall(tcx: TyCtxt,
                 msg: &str,
                 li: LangItem)
                 -> DefId {
-    match tcx.lang_items().require(li) {
-        Ok(id) => id,
-        Err(s) => {
-            let msg = format!("{} {}", msg, s);
-            match span {
-                Some(span) => tcx.sess.span_fatal(span, &msg[..]),
-                None => tcx.sess.fatal(&msg[..]),
-            }
+    tcx.lang_items().require(li).unwrap_or_else(|s| {
+        let msg = format!("{} {}", msg, s);
+        match span {
+            Some(span) => tcx.sess.span_fatal(span, &msg[..]),
+            None => tcx.sess.fatal(&msg[..]),
         }
-    }
+    })
 }
 
 // To avoid UB from LLVM, these two functions mask RHS with an
diff --git a/src/librustc_codegen_llvm/consts.rs b/src/librustc_codegen_llvm/consts.rs
index 487f3e0759d..9228870bf3a 100644
--- a/src/librustc_codegen_llvm/consts.rs
+++ b/src/librustc_codegen_llvm/consts.rs
@@ -249,14 +249,13 @@ fn check_and_apply_linkage(
         // extern "C" fn() from being non-null, so we can't just declare a
         // static and call it a day. Some linkages (like weak) will make it such
         // that the static actually has a null value.
-        let llty2 = match ty.sty {
-            ty::RawPtr(ref mt) => cx.layout_of(mt.ty).llvm_type(cx),
-            _ => {
-                if span.is_some() {
-                    cx.sess().span_fatal(span.unwrap(), "must have type `*const T` or `*mut T`")
-                } else {
-                    bug!("must have type `*const T` or `*mut T`")
-                }
+        let llty2 = if let ty::RawPtr(ref mt) = ty.sty {
+            cx.layout_of(mt.ty).llvm_type(cx)
+        } else {
+            if let Some(span) = span {
+                cx.sess().span_fatal(span, "must have type `*const T` or `*mut T`")
+            } else {
+                bug!("must have type `*const T` or `*mut T`")
             }
         };
         unsafe {
@@ -273,9 +272,9 @@ fn check_and_apply_linkage(
             let mut real_name = "_rust_extern_with_linkage_".to_string();
             real_name.push_str(&sym);
             let g2 = declare::define_global(cx, &real_name, llty).unwrap_or_else(||{
-                if span.is_some() {
+                if let Some(span) = span {
                     cx.sess().span_fatal(
-                        span.unwrap(),
+                        span,
                         &format!("symbol `{}` is already defined", &sym)
                     )
                 } else {
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 67f7a609c48..60cdea29fb7 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -318,10 +318,8 @@ impl<'b, 'tcx> CodegenCx<'b, 'tcx> {
         if let Some(v) = self.intrinsics.borrow().get(key).cloned() {
             return v;
         }
-        match declare_intrinsic(self, key) {
-            Some(v) => return v,
-            None => bug!("unknown intrinsic '{}'", key)
-        }
+
+        declare_intrinsic(self, key).unwrap_or_else(|| bug!("unknown intrinsic '{}'", key))
     }
 
     /// Generate a new symbol name with the given prefix. This symbol name must
@@ -465,9 +463,10 @@ impl LayoutOf for &'a CodegenCx<'ll, 'tcx> {
 
     fn layout_of(self, ty: Ty<'tcx>) -> Self::TyLayout {
         self.tcx.layout_of(ty::ParamEnv::reveal_all().and(ty))
-            .unwrap_or_else(|e| match e {
-                LayoutError::SizeOverflow(_) => self.sess().fatal(&e.to_string()),
-                _ => bug!("failed to get layout for `{}`: {}", ty, e)
+            .unwrap_or_else(|e| if let LayoutError::SizeOverflow(_) = e {
+                self.sess().fatal(&e.to_string())
+            } else {
+                bug!("failed to get layout for `{}`: {}", ty, e)
             })
     }
 }
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 74326f8a08e..9e6c84071f7 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -539,10 +539,9 @@ pub fn codegen_intrinsic_call(
         }
 
         _ => {
-            let intr = match Intrinsic::find(&name) {
-                Some(intr) => intr,
-                None => bug!("unknown intrinsic '{}'", name),
-            };
+            let intr = Intrinsic::find(&name).unwrap_or_else(||
+                bug!("unknown intrinsic '{}'", name));
+
             fn one<T>(x: Vec<T>) -> T {
                 assert_eq!(x.len(), 1);
                 x.into_iter().next().unwrap()
@@ -1071,11 +1070,8 @@ fn generic_simd_intrinsic(
     }
 
     if name.starts_with("simd_shuffle") {
-        let n: usize = match name["simd_shuffle".len()..].parse() {
-            Ok(n) => n,
-            Err(_) => span_bug!(span,
-                                "bad `simd_shuffle` instruction only caught in codegen?")
-        };
+        let n: usize = name["simd_shuffle".len()..].parse().unwrap_or_else(|_|
+            span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?"));
 
         require_simd!(ret_ty, "return");
 
@@ -1216,63 +1212,53 @@ fn generic_simd_intrinsic(
                         &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
                         None);
         unsafe { llvm::LLVMRustSetHasUnsafeAlgebra(c) };
-        return Ok(c);
-    }
-
-    if name == "simd_fsqrt" {
-        return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fsin" {
-        return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fcos" {
-        return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fabs" {
-        return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
+        Ok(c)
     }
 
-    if name == "simd_floor" {
-        return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_ceil" {
-        return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fexp" {
-        return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fexp2" {
-        return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_flog10" {
-        return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_flog2" {
-        return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_flog" {
-        return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fpowi" {
-        return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fpow"  {
-        return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
-    }
-
-    if name == "simd_fma" {
-        return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
+    match name {
+        "simd_fsqrt" => {
+            return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fsin" => {
+            return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fcos" => {
+            return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fabs" => {
+            return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_floor" => {
+            return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_ceil" => {
+            return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fexp" => {
+            return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fexp2" => {
+            return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_flog10" => {
+            return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_flog2" => {
+            return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_flog" => {
+            return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fpowi" => {
+            return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fpow" => {
+            return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
+        }
+        "simd_fma" => {
+            return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
+        }
+        _ => { /* fallthrough */ }
     }
 
     // FIXME: use:
@@ -1364,7 +1350,7 @@ fn generic_simd_intrinsic(
             }
         };
         assert!(pointer_count > 0);
-        assert!(pointer_count - 1 == ptr_count(arg_tys[0].simd_type(tcx)));
+        assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
 
         // The element type of the third argument must be a signed integer type of any width:
@@ -1461,7 +1447,7 @@ fn generic_simd_intrinsic(
             }
         };
         assert!(pointer_count > 0);
-        assert!(pointer_count - 1 == ptr_count(arg_tys[0].simd_type(tcx)));
+        assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
 
         // The element type of the third argument must be a signed integer type of any width:
diff --git a/src/librustc_codegen_llvm/type_of.rs b/src/librustc_codegen_llvm/type_of.rs
index 2fa784161bd..03ded64e642 100644
--- a/src/librustc_codegen_llvm/type_of.rs
+++ b/src/librustc_codegen_llvm/type_of.rs
@@ -65,13 +65,12 @@ fn uncached_llvm_type<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
             let mut name = String::with_capacity(32);
             let printer = DefPathBasedNames::new(cx.tcx, true, true);
             printer.push_type_name(layout.ty, &mut name);
-            match (&layout.ty.sty, &layout.variants) {
-                (&ty::Adt(def, _), &layout::Variants::Single { index }) => {
-                    if def.is_enum() && !def.variants.is_empty() {
-                        write!(&mut name, "::{}", def.variants[index].name).unwrap();
-                    }
+            if let (&ty::Adt(def, _), &layout::Variants::Single { index })
+                 = (&layout.ty.sty, &layout.variants)
+            {
+                if def.is_enum() && !def.variants.is_empty() {
+                    write!(&mut name, "::{}", def.variants[index].name).unwrap();
                 }
-                _ => {}
             }
             Some(name)
         }
@@ -155,7 +154,7 @@ fn struct_llfields<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
         debug!("struct_llfields: pad_bytes: {:?} offset: {:?} stride: {:?}",
                padding, offset, layout.size);
         result.push(Type::padding_filler(cx, padding, padding_align));
-        assert!(result.len() == 1 + field_count * 2);
+        assert_eq!(result.len(), 1 + field_count * 2);
     } else {
         debug!("struct_llfields: offset: {:?} stride: {:?}",
                offset, layout.size);