0.9.3.2:

	Micro-optimizations:
	* MAKE-FIXNUM on PPC now takes one instruction rather than two;
	* signed-num INTEGER-LENGTH VOP on PPC does not require a
          temporary register;
	* Added unsigned-num INTEGER-LENGTH VOP on PPC;
	* Musings on processor-specific micro-optimizations added to
	  OPTIMIZATIONS.

diff --git a/OPTIMIZATIONS b/OPTIMIZATIONS
index a702c7d..c79f922 100644 (file)
--- a/OPTIMIZATIONS
+++ b/OPTIMIZATIONS
@@ -231,4 +231,37 @@ it could be; if we placed raw slots before the header word, we would
 not need to do arithmetic at runtime to access them.  (But beware:
 this would complicate handling of the interior pointer).
 
-b. (Also note that raw slots are currently disabled on HPPA)
\ No newline at end of file
+b. (Also note that raw slots are currently disabled on HPPA)
+--------------------------------------------------------------------------------
+#29
+Python is overly zealous when converting high-level CL functions, such
+as MIN/MAX, LOGBITP, and LOGTEST, to low-level CL functions.  Reducing
+Python's aggressiveness would make it easier to effect changes such as
+
+x86-64:
+* direct MIN/MAX on {SINGLE,DOUBLE}-FLOATs ({MIN,MAX}S{S,D})
+
+x86{,-64}:
+* direct LOGBITP on word-sized integers and fixnums (BT + JC)
+
+x86{,-64}/PPC:
+* branch-free MIN/MAX on word-sized integers and fixnums
+* efficient LOGTESTs on word-sized integers and fixnums (TEST / AND.)
+
+PPC:
+* efficient LDB on word-sized integers and fixnums (RLWINM)
+
+etc., etc.
+
+The "easier" part claimed above would come about because the functions
+would be available for :TRANSLATE through a VOP or similar, whereas with
+the current architecture, one would have to pattern-match IR1.  While
+IR1 pattern-matching would be useful in other contexts, it seems better
+here to attempt the direct :TRANSLATE route.
+
+I (NJF) don't know how to implement such architecture-specific
+optimizations whilst keeping the high->low transformations for other
+architectures.  Certainly adding #!+/- magic in compiler/*.lisp could be
+done, but such a solution is somewhat inelegant.  Moving the relevant
+DEFTRANSFORMs to the architecture-specific compiler/* areas is also
+possible, but that would duplicate quite a bit of code.

diff --git a/src/compiler/ppc/arith.lisp b/src/compiler/ppc/arith.lisp
index ee7a851..c633a13 100644 (file)
--- a/src/compiler/ppc/arith.lisp
+++ b/src/compiler/ppc/arith.lisp
@@ -614,19 +614,29 @@
   (:policy :fast-safe)
   (:args (arg :scs (signed-reg)))
   (:arg-types signed-num)
-  (:results (res :scs (any-reg)))
-  (:result-types positive-fixnum)
-  (:temporary (:scs (non-descriptor-reg) :to (:argument 0)) shift)
+  (:results (res :scs (unsigned-reg)))
+  (:result-types unsigned-num)
   (:generator 6
     ; (integer-length arg) = (- 32 (cntlz (if (>= arg 0) arg (lognot arg))))
     (let ((nonneg (gen-label)))
-      (inst cntlzw. shift arg)
+      (inst cntlzw. res arg)
       (inst bne nonneg)
-      (inst not shift arg)
-      (inst cntlzw shift shift)
+      (inst not res arg)
+      (inst cntlzw res res)
       (emit-label nonneg)
-      (inst slwi shift shift 2)
-      (inst subfic res  shift (fixnumize 32)))))
+      (inst subfic res res 32))))
+
+(define-vop (unsigned-byte-32-len)
+  (:translate integer-length)
+  (:note "inline (unsigned-byte 32) integer-length")
+  (:policy :fast-safe)
+  (:args (arg :scs (unsigned-reg)))
+  (:arg-types unsigned-num)
+  (:results (res :scs (unsigned-reg)))
+  (:result-types unsigned-num)
+  (:generator 4
+    (inst cntlzw res arg)
+    (inst subfic res res 32)))
 
 (define-vop (unsigned-byte-32-count)
   (:translate logcount)

diff --git a/src/compiler/ppc/insts.lisp b/src/compiler/ppc/insts.lisp
index 9dceec4..b14927a 100644 (file)
--- a/src/compiler/ppc/insts.lisp
+++ b/src/compiler/ppc/insts.lisp
@@ -1828,6 +1828,12 @@
   (define-instruction-macro extlwi. (ra rs n b)
     `(inst rlwinm. ,ra ,rs ,b 0 (1- ,n)))
 
+  (define-instruction-macro extrwi (ra rs n b)
+    `(inst rlwinm ,ra ,rs (mod (+ ,b ,n) 32) (- 32 ,n) 31))
+
+  (define-instruction-macro extrwi. (ra rs n b)
+    `(inst rlwinm. ,ra ,rs (mod (+ ,b ,n) 32) (- 32 ,n) 31))
+
   (define-instruction-macro srwi (ra rs n)
     `(inst rlwinm ,ra ,rs (- 32 ,n) ,n 31))
 

diff --git a/src/compiler/ppc/system.lisp b/src/compiler/ppc/system.lisp
index 6a437e1..d640ab9 100644 (file)
--- a/src/compiler/ppc/system.lisp
+++ b/src/compiler/ppc/system.lisp
@@ -128,8 +128,7 @@
     ;;
     ;; Some code (the hash table code) depends on this returning a
     ;; positive number so make sure it does.
-    (inst slwi res ptr 3)
-    (inst srwi res res 1)))
+    (inst rlwinm res ptr n-fixnum-tag-bits 1 n-positive-fixnum-bits)))
 
 (define-vop (make-other-immediate-type)
   (:args (val :scs (any-reg descriptor-reg))

diff --git a/version.lisp-expr b/version.lisp-expr
index 8b044a6..01c4735 100644 (file)
--- a/version.lisp-expr
+++ b/version.lisp-expr
@@ -17,4 +17,4 @@
 ;;; checkins which aren't released. (And occasionally for internal
 ;;; versions, especially for internal versions off the main CVS
 ;;; branch, it gets hairier, e.g. "0.pre7.14.flaky4.13".)
-"0.9.3.1"
+"0.9.3.2"