[Docs] update MemorySSA for opaque ptrs

Reviewed By: asbirlea, nikic

Differential Revision: https://reviews.llvm.org/D145130

llvm/docs/MemorySSA.rst

@@ -124,7 +124,7 @@ the value is the new version of the memory after the operation.
     %p2 = alloca i8
     %p3 = alloca i8
     ; 1 = MemoryDef(liveOnEntry)
-    store i8 0, i8* %p3
+    store i8 0, ptr %p3
     br label %while.cond
 
   while.cond:
@@ -133,30 +133,30 @@ the value is the new version of the memory after the operation.
 
   if.then:
     ; 2 = MemoryDef(6)
-    store i8 0, i8* %p1
+    store i8 0, ptr %p1
     br label %if.end
 
   if.else:
     ; 3 = MemoryDef(6)
-    store i8 1, i8* %p2
+    store i8 1, ptr %p2
     br label %if.end
 
   if.end:
     ; 5 = MemoryPhi({if.then,2},{if.else,3})
     ; MemoryUse(5)
-    %1 = load i8, i8* %p1
+    %1 = load i8, ptr %p1
     ; 4 = MemoryDef(5)
-    store i8 2, i8* %p2
+    store i8 2, ptr %p2
     ; MemoryUse(1)
-    %2 = load i8, i8* %p3
+    %2 = load i8, ptr %p3
     br label %while.cond
   }
 
 The ``MemorySSA`` IR is shown in comments that precede the instructions they map
 to (if such an instruction exists). For example, ``1 = MemoryDef(liveOnEntry)``
 is a ``MemoryAccess`` (specifically, a ``MemoryDef``), and it describes the LLVM
-instruction ``store i8 0, i8* %p3``. Other places in ``MemorySSA`` refer to this
-particular ``MemoryDef`` as ``1`` (much like how one can refer to ``load i8, i8*
+instruction ``store i8 0, ptr %p3``. Other places in ``MemorySSA`` refer to this
+particular ``MemoryDef`` as ``1`` (much like how one can refer to ``load i8, ptr
 %p1`` in LLVM with ``%1``). Again, ``MemoryPhi``\ s don't correspond to any LLVM
 Instruction, so the line directly below a ``MemoryPhi`` isn't special.
 
@@ -165,20 +165,20 @@ Going from the top down:
 - ``6 = MemoryPhi({entry,1},{if.end,4})`` notes that, when entering
   ``while.cond``, the reaching definition for it is either ``1`` or ``4``. This
   ``MemoryPhi`` is referred to in the textual IR by the number ``6``.
-- ``2 = MemoryDef(6)`` notes that ``store i8 0, i8* %p1`` is a definition,
+- ``2 = MemoryDef(6)`` notes that ``store i8 0, ptr %p1`` is a definition,
   and its reaching definition before it is ``6``, or the ``MemoryPhi`` after
   ``while.cond``. (See the `Use and Def optimization`_ and `Precision`_
   sections below for why this ``MemoryDef`` isn't linked to a separate,
   disambiguated ``MemoryPhi``.)
-- ``3 = MemoryDef(6)`` notes that ``store i8 0, i8* %p2`` is a definition; its
+- ``3 = MemoryDef(6)`` notes that ``store i8 0, ptr %p2`` is a definition; its
   reaching definition is also ``6``.
 - ``5 = MemoryPhi({if.then,2},{if.else,3})`` notes that the clobber before
   this block could either be ``2`` or ``3``.
-- ``MemoryUse(5)`` notes that ``load i8, i8* %p1`` is a use of memory, and that
+- ``MemoryUse(5)`` notes that ``load i8, ptr %p1`` is a use of memory, and that
   it's clobbered by ``5``.
-- ``4 = MemoryDef(5)`` notes that ``store i8 2, i8* %p2`` is a definition; its
+- ``4 = MemoryDef(5)`` notes that ``store i8 2, ptr %p2`` is a definition; its
   reaching definition is ``5``.
-- ``MemoryUse(1)`` notes that ``load i8, i8* %p3`` is just a user of memory,
+- ``MemoryUse(1)`` notes that ``load i8, ptr %p3`` is just a user of memory,
   and the last thing that could clobber this use is above ``while.cond`` (e.g.
   the store to ``%p3``). In memory versioning parlance, it really only depends on
   the memory version 1, and is unaffected by the new memory versions generated since
@@ -215,9 +215,9 @@ given:
     %b = alloca i8
 
     ; 1 = MemoryDef(liveOnEntry)
-    store i8 0, i8* %a
+    store i8 0, ptr %a
     ; 2 = MemoryDef(1)
-    store i8 0, i8* %b
+    store i8 0, ptr %b
   }
 
 The store to ``%a`` is clearly not a clobber for the store to ``%b``. It would
@@ -359,7 +359,7 @@ example, consider:
     %p2 = alloca i8
     %p3 = alloca i8
     ; 1 = MemoryDef(liveOnEntry)
-    store i8 0, i8* %p3
+    store i8 0, ptr %p3
     br label %while.cond
 
   while.cond:
@@ -374,11 +374,11 @@ example, consider:
 
   if.end:
     ; MemoryUse(1)
-    %1 = load i8, i8* %p1
+    %1 = load i8, ptr %p1
     ; 2 = MemoryDef(3)
-    store i8 2, i8* %p2
+    store i8 2, ptr %p2
     ; MemoryUse(1)
-    %2 = load i8, i8* %p3
+    %2 = load i8, ptr %p3
     br label %while.cond
   }
 
@@ -403,13 +403,13 @@ to reason about atomic or volatile operations, as in:
 
 .. code-block:: llvm
 
-  define i8 @foo(i8* %a) {
+  define i8 @foo(ptr %a) {
   entry:
     br i1 undef, label %if.then, label %if.end
 
   if.then:
     ; 1 = MemoryDef(liveOnEntry)
-    %0 = load volatile i8, i8* %a
+    %0 = load volatile i8, ptr %a
     br label %if.end
 
   if.end: