[Issue 5563] New: Failed/succeeded inlining listing

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=5563

           Summary: Failed/succeeded inlining listing
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody at puremagic.com
        ReportedBy: bearophile_hugs at eml.cc


--- Comment #0 from bearophile_hugs at eml.cc 2011-02-11 03:25:22 PST ---
Inlining is one of the most important performance optimizations, so an useful
information for the programmer is a list of failed/succeeded inlining points.
See:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=129206

Taking a look at the produced asm is often enough to see where inlining has
happened or not, but a list shown by the compiler is simpler and quicker to
read and understand, for external automatic tools too.

When you compile CommonLisp with max optimization levels the compiler gives
many comments that explain why it isn't optimizing something, including some
forms of inlining, see for example:

http://shootout.alioth.debian.org/u32/program.php?test=fasta&lang=sbcl&id=3

Example of the comments:

; file: /home/dunham/shootout/bench/fasta/fasta.sbcl-3.sbcl
; in: DEFUN CUMSUM
;     (CEILING (* +IM+ (INCF C X)))
; --> CEILING MULTIPLE-VALUE-BIND MULTIPLE-VALUE-CALL TRUNCATE LET 
; ==>
;   (SB-KERNEL:%UNARY-TRUNCATE/SINGLE-FLOAT SB-C::X)
; 
; note: forced to do full call
;       unable to do inline float truncate (cost 5) because:
;       The result is a (VALUES INTEGER &OPTIONAL), not a (VALUES
;                                                          (SIGNED-BYTE 32)
&REST
;                                                          T).
;       unable to do inline float truncate (cost 5) because:
;       The result is a (VALUES INTEGER &OPTIONAL), not a (VALUES
;                                                          (UNSIGNED-BYTE 32)
;                                                          &REST T).

; --> CEILING MULTIPLE-VALUE-BIND MULTIPLE-VALUE-CALL TRUNCATE LET VALUES - 
; ==>
;   (SB-KERNEL:%SINGLE-FLOAT SB-C::RES)
; 
; note: forced to do full call
;       unable to do inline float coercion (cost 5) because:
;       The first argument is a INTEGER, not a (SIGNED-BYTE 32).
;       unable to do inline float coercion (cost 6) because:
;       The first argument is a INTEGER, not a (UNSIGNED-BYTE 32).

...


Another similar kind of useful notes from the compiler:
http://d.puremagic.com/issues/show_bug.cgi?id=5070

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