manpage: optimization section

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@@ -336,6 +336,30 @@ instruction on the string before using it.
 Enable utf8 characters. This allows utf-8 encoded character constants,
 and escape sequence codepoints in the valid utf-8 range. Effectively
 enabling escape sequences like '\\{x2211}'.
+.SH OPTIMIZATIONS
+.TP
+.B -Opeephole
+Some general peephole optimizations. For instance the code `a = b + c`
+typically generates 2 instructions, an ADD and a STORE. This
+optimization removes the STORE and lets the ADD write directly into A.
+This optimization will not happen for MUL_VF or MUL_FV if the target
+is the float operand.
+.TP
+.B -Otail-recursion
+Tail recursive function calls will be turned into loops to avoid the
+overhead of the CALL and RETURN instructions.
+.TP
+.B -Ooverlap-locals
+Make all functions which use neither local arrays nor have locals
+which are seen as possibly uninitialized use the same local section.
+This should be pretty safe compared to other compilers which do not
+check for uninitialized values properly. The problem is that there's
+QC code out there which really doesn't initialize some values. This is
+fine as long as this kind of optimization isn't used, but also, only
+as long as the functions cannot be called in a recursive manner. Since
+it's hard to know whether or not an array is actually fully
+initialized, especially when initializing it via a loop, we assume
+functions with arrays to be too dangerous for this optimization.
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