more edits from Jon Sargeant

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49065 91177308-0d34-0410-b5e6-96231b3b80d8

docs/LangRef.html

@@ -2787,7 +2787,7 @@ address space (address space zero).</p>
 bytes of memory from the operating system and returns a pointer of the
 appropriate type to the program.  If "NumElements" is specified, it is the
 number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If an alignment is specified, the value result of the allocation is guaranteed to
+If a constant alignment is specified, the value result of the allocation is guaranteed to
 be aligned to at least that boundary.  If not specified, or if zero, the target can
 choose to align the allocation on any convenient boundary.</p>
 
@@ -2796,7 +2796,8 @@ choose to align the allocation on any convenient boundary.</p>
 <h5>Semantics:</h5>
 
 <p>Memory is allocated using the system "<tt>malloc</tt>" function, and
-a pointer is returned.</p>
+a pointer is returned.  Allocating zero bytes is undefined.  The result is null
+if there is insufficient memory available.</p>
 
 <h5>Example:</h5>
 
@@ -2838,7 +2839,8 @@ instruction.</p>
 <h5>Semantics:</h5>
 
 <p>Access to the memory pointed to by the pointer is no longer defined
-after this instruction executes.</p>
+after this instruction executes.  If the pointer is null, the result is
+undefined.</p>
 
 <h5>Example:</h5>
 
@@ -2874,7 +2876,7 @@ space (address space zero).</p>
 bytes of memory on the runtime stack, returning a pointer of the
 appropriate type to the program.  If "NumElements" is specified, it is the
 number of elements allocated, otherwise "NumElements" is defaulted to be one.
-If an alignment is specified, the value result of the allocation is guaranteed
+If a constant alignment is specified, the value result of the allocation is guaranteed
 to be aligned to at least that boundary.  If not specified, or if zero, the target
 can choose to align the allocation on any convenient boundary.</p>
 
@@ -2887,7 +2889,8 @@ memory is automatically released when the function returns.  The '<tt>alloca</tt
 instruction is commonly used to represent automatic variables that must
 have an address available.  When the function returns (either with the <tt><a
  href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
-instructions), the memory is reclaimed.</p>
+instructions), the memory is reclaimed.  Allocating zero bytes
+is legal, but the result is undefined.</p>
 
 <h5>Example:</h5>
 
@@ -2916,7 +2919,7 @@ the number or order of execution of this <tt>load</tt> with other
 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
 instructions. </p>
 <p>
-The optional "align" argument specifies the alignment of the operation
+The optional constant "align" argument specifies the alignment of the operation
 (that is, the alignment of the memory address). A value of 0 or an
 omitted "align" argument means that the operation has the preferential
 alignment for the target. It is the responsibility of the code emitter
@@ -2947,13 +2950,14 @@ Instruction</a> </div>
 <h5>Arguments:</h5>
 <p>There are two arguments to the '<tt>store</tt>' instruction: a value
 to store and an address at which to store it.  The type of the '<tt>&lt;pointer&gt;</tt>'
-operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
+operand must be a pointer to the <a href="#t_firstclass">first class</a> type
+of the '<tt>&lt;value&gt;</tt>'
 operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
 optimizer is not allowed to modify the number or order of execution of
 this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
  href="#i_store">store</a></tt> instructions.</p>
 <p>
-The optional "align" argument specifies the alignment of the operation
+The optional constant "align" argument specifies the alignment of the operation
 (that is, the alignment of the memory address). A value of 0 or an
 omitted "align" argument means that the operation has the preferential
 alignment for the target. It is the responsibility of the code emitter
@@ -3043,8 +3047,8 @@ entry:
 on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
 and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
 <a href="#t_integer">integer</a> type but the value will always be sign extended
-to 64-bits.  <a href="#t_struct">Structure</a> types require <tt>i32</tt>
+to 64-bits.  <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
-<b>constants</b>.</p>
+structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
 
 <p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
@@ -3552,7 +3556,7 @@ instructions, which defy better classification.</p>
 </pre>
 <h5>Overview:</h5>
 <p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
-of its two integer operands.</p>
+of its two integer or pointer operands.</p>
 <h5>Arguments:</h5>
 <p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
 the condition code indicating the kind of comparison to perform. It is not
@@ -3918,7 +3922,7 @@ results.</p>
 
 <p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its 
 first argument.  The value must have <a href="#t_struct">structure type</a>. 
-The second argument is an unsigned index value which must be in range for 
+The second argument is a constant unsigned index value which must be in range for
 the number of values returned by the call.</p>
 
 <h5>Semantics:</h5>