[WebAssembly] Improve readability of load/stores and tests. NFC.

Summary:
- Changed variable/function names to be more consistent
- Improved comments in test files
- Added more tests
- Fixed a few typos
- Misc. cosmetic changes

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D49087

llvm-svn: 336598
diff --git a/llvm/test/CodeGen/WebAssembly/i64-load-store-alignment.ll b/llvm/test/CodeGen/WebAssembly/i64-load-store-alignment.ll
index f3b8e15..eb303c1 100644
--- a/llvm/test/CodeGen/WebAssembly/i64-load-store-alignment.ll
+++ b/llvm/test/CodeGen/WebAssembly/i64-load-store-alignment.ll
@@ -5,7 +5,9 @@
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
-; Loads.
+;===----------------------------------------------------------------------------
+; Loads
+;===----------------------------------------------------------------------------
 
 ; CHECK-LABEL: ldi64_a1:
 ; CHECK-NEXT: .param i32{{$}}
@@ -73,7 +75,9 @@
   ret i64 %v
 }
 
-; Extending loads.
+;===----------------------------------------------------------------------------
+; Extending loads
+;===----------------------------------------------------------------------------
 
 ; CHECK-LABEL: ldi8_a1:
 ; CHECK-NEXT: .param i32{{$}}
@@ -174,7 +178,9 @@
   ret i64 %w
 }
 
-; Stores.
+;===----------------------------------------------------------------------------
+; Stores
+;===----------------------------------------------------------------------------
 
 ; CHECK-LABEL: sti64_a1:
 ; CHECK-NEXT: .param i32, i64{{$}}
@@ -234,7 +240,9 @@
   ret void
 }
 
-; Truncating stores.
+;===----------------------------------------------------------------------------
+; Truncating stores
+;===----------------------------------------------------------------------------
 
 ; CHECK-LABEL: sti8_a1:
 ; CHECK-NEXT: .param i32, i64{{$}}
@@ -326,7 +334,10 @@
   ret void
 }
 
-; Atomics.
+;===----------------------------------------------------------------------------
+; Atomic loads
+;===----------------------------------------------------------------------------
+
 ; Wasm atomics have the alignment field, but it must always have the type's
 ; natural alignment.
 
@@ -341,6 +352,7 @@
 }
 
 ; 16 is greater than the default alignment so it is ignored.
+
 ; CHECK-LABEL: ldi64_atomic_a16:
 ; CHECK-NEXT: .param i32{{$}}
 ; CHECK-NEXT: .result i64{{$}}
@@ -351,6 +363,10 @@
   ret i64 %v
 }
 
+;===----------------------------------------------------------------------------
+; Atomic stores
+;===----------------------------------------------------------------------------
+
 ; CHECK-LABEL: sti64_atomic_a4:
 ; CHECK-NEXT: .param i32, i64{{$}}
 ; CHECK-NEXT: i64.atomic.store 0($0), $1{{$}}
@@ -361,6 +377,7 @@
 }
 
 ; 16 is greater than the default alignment so it is ignored.
+
 ; CHECK-LABEL: sti64_atomic_a8:
 ; CHECK-NEXT: .param i32, i64{{$}}
 ; CHECK-NEXT: i64.atomic.store 0($0), $1{{$}}