From cc1dd45568ca36ef7ace7a996758944f2f90f514 Mon Sep 17 00:00:00 2001
From: Vincent St-Amour <stamourv@racket-lang.org>
Date: Sat, 13 Oct 2012 17:49:48 -0400
Subject: [PATCH] More float conversion optimizations.

original commit: 149d8535eb2988fab0bed739d375874f172db7c8
---
 .../optimizer/tests/exact-inexact.rkt         | 21 +++++++++++++++++-
 collects/typed-racket/optimizer/float.rkt     | 22 +++++++++++++++++--
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/collects/tests/typed-racket/optimizer/tests/exact-inexact.rkt b/collects/tests/typed-racket/optimizer/tests/exact-inexact.rkt
index 245c7255..5fc0cb2a 100644
--- a/collects/tests/typed-racket/optimizer/tests/exact-inexact.rkt
+++ b/collects/tests/typed-racket/optimizer/tests/exact-inexact.rkt
@@ -1,10 +1,29 @@
 #;
 (
-TR opt: exact-inexact.rkt 10:0 (exact->inexact (expt 10 100)) -- int to float
+TR opt: exact-inexact.rkt 22:0 (exact->inexact (expt 10 100)) -- int to float
+TR opt: exact-inexact.rkt 23:7 (exact->inexact (expt 2.3 3.2)) -- float to float
+TR opt: exact-inexact.rkt 23:0 (round (exact->inexact (expt 2.3 3.2))) -- unary float
+TR opt: exact-inexact.rkt 24:0 (real->double-flonum (expt 10 100)) -- int to float
+TR opt: exact-inexact.rkt 25:7 (real->double-flonum (expt 2.3 3.2)) -- float to float
+TR opt: exact-inexact.rkt 25:0 (round (real->double-flonum (expt 2.3 3.2))) -- unary float
+TR opt: exact-inexact.rkt 28:0 (exact->inexact (expt 1.0f0 2.0f0)) -- single-float to single-float
+TR opt: exact-inexact.rkt 29:0 (real->single-flonum (expt 1.0f0 2.0f0)) -- single-float to single-float
 1e+100
+14.0
+1e+100
+14.0
+1.0f0
+1.0f0
 )
 
 #lang typed/scheme
 #:optimize
 
 (exact->inexact (expt 10 100)) ; must not be a fixnum
+(round (exact->inexact (expt 2.3 3.2))) ; already a float
+(real->double-flonum (expt 10 100)) ; must not be a fixnum
+(round (real->double-flonum (expt 2.3 3.2))) ; already a float
+
+;; single floats
+(exact->inexact (expt 1.0f0 2.0f0))
+(real->single-flonum (expt 1.0f0 2.0f0))
diff --git a/collects/typed-racket/optimizer/float.rkt b/collects/typed-racket/optimizer/float.rkt
index a46b0cc6..78efa0b2 100644
--- a/collects/typed-racket/optimizer/float.rkt
+++ b/collects/typed-racket/optimizer/float.rkt
@@ -40,6 +40,11 @@
   (pattern e:expr
            #:when (subtypeof? #'e -Flonum)
            #:with opt ((optimize) #'e)))
+(define-syntax-class single-float-expr
+  #:commit
+  (pattern e:expr
+           #:when (subtypeof? #'e -SingleFlonum)
+           #:with opt ((optimize) #'e)))
 (define-syntax-class int-expr
   #:commit
   (pattern e:expr
@@ -188,17 +193,30 @@
                   #'(let ([tmp f.opt]) (unsafe-fl* tmp tmp))))
 
   ;; we can optimize exact->inexact if we know we're giving it an Integer
-  (pattern (#%plain-app (~and op (~literal exact->inexact)) n:int-expr)
+  (pattern (#%plain-app (~and op (~or (~literal exact->inexact)
+                                      (~literal real->double-flonum)))
+                        n:int-expr)
            #:with opt
            (begin (log-optimization "int to float" float-opt-msg this-syntax)
                   (add-disappeared-use #'op)
                   #'(->fl n.opt)))
   ;; we can get rid of it altogether if we're giving it a float
-  (pattern (#%plain-app (~and op (~literal exact->inexact)) f:float-expr)
+  (pattern (#%plain-app (~and op (~or (~literal exact->inexact)
+                                      (~literal real->double-flonum)))
+                        f:float-expr)
            #:with opt
            (begin (log-optimization "float to float" float-opt-msg this-syntax)
                   (add-disappeared-use #'op)
                   #'f.opt))
+  ;; same for single-flonums
+  (pattern (#%plain-app (~and op (~or (~literal exact->inexact)
+                                      (~literal real->single-flonum)))
+                        f:single-float-expr)
+           #:with opt
+           (begin (log-optimization "single-float to single-float"
+                                    float-opt-msg this-syntax)
+                  (add-disappeared-use #'op)
+                  #'f.opt))
 
   (pattern (#%plain-app (~and op (~literal zero?)) f:float-expr)
            #:with opt