X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fir1opt.lisp;h=11021125a30a02e9235570c4386b5ecce8b17dc3;hb=559d0ded238d8ec852fcd485656ef14578fc405f;hp=7e83244f2761bc907c241c9f529084f90a60a257;hpb=aa6ba297065841d20261cbe3cece624465d0edf1;p=sbcl.git

diff --git a/src/compiler/ir1opt.lisp b/src/compiler/ir1opt.lisp
index 7e83244..1102112 100644
--- a/src/compiler/ir1opt.lisp
+++ b/src/compiler/ir1opt.lisp
@@ -637,6 +637,14 @@
 #!+sb-show
 (defvar *show-transforms-p* nil)
 
+(defun check-important-result (node info)
+  (when (and (null (node-lvar node))
+             (ir1-attributep (fun-info-attributes info) important-result))
+    (let ((*compiler-error-context* node))
+      (compiler-style-warn
+       "The return value of ~A should not be discarded."
+       (lvar-fun-name (basic-combination-fun node))))))
+
 ;;; Do IR1 optimizations on a COMBINATION node.
 (declaim (ftype (function (combination) (values)) ir1-optimize-combination))
 (defun ir1-optimize-combination (node)
@@ -661,6 +669,7 @@
          (when arg
            (setf (lvar-reoptimize arg) nil)))
        (when info
+         (check-important-result node info)
          (let ((fun (fun-info-destroyed-constant-args info)))
            (when fun
              (let ((destroyed-constant-args (funcall fun args)))
@@ -682,7 +691,7 @@
        (dolist (arg args)
          (when arg
            (setf (lvar-reoptimize arg) nil)))
-
+       (check-important-result node info)
        (let ((fun (fun-info-destroyed-constant-args info)))
          (when fun
            (let ((destroyed-constant-args (funcall fun args)))
@@ -1217,20 +1226,28 @@
                       (eq (combination-kind set-use) :known)
                       (fun-info-p (combination-fun-info set-use))
                       (not (node-to-be-deleted-p set-use))
-                      (eq (combination-fun-source-name set-use) '+))
-               :exit-if-null)
+                      (or (eq (combination-fun-source-name set-use) '+)
+                          (eq (combination-fun-source-name set-use) '-)))
+              :exit-if-null)
+             (minusp (eq (combination-fun-source-name set-use) '-))
              (+-args (basic-combination-args set-use))
              (() (and (proper-list-of-length-p +-args 2 2)
                       (let ((first (principal-lvar-use
                                     (first +-args))))
                         (and (ref-p first)
                              (eq (ref-leaf first) var))))
-               :exit-if-null)
+              :exit-if-null)
              (step-type (lvar-type (second +-args)))
              (set-type (lvar-type (set-value set))))
     (when (and (numeric-type-p initial-type)
                (numeric-type-p step-type)
-               (numeric-type-equal initial-type step-type))
+               (or (numeric-type-equal initial-type step-type)
+                   ;; Detect cases like (LOOP FOR 1.0 to 5.0 ...), where
+                   ;; the initial and the step are of different types,
+                   ;; and the step is less contagious.
+                   (numeric-type-equal initial-type
+                                       (numeric-contagion initial-type
+                                                          step-type))))
       (labels ((leftmost (x y cmp cmp=)
                  (cond ((eq x nil) nil)
                        ((eq y nil) nil)
@@ -1247,22 +1264,27 @@
                        (t (if (funcall cmp x y) x y))))
                (max* (x y) (leftmost x y #'> #'>=))
                (min* (x y) (leftmost x y #'< #'<=)))
-        (declare (inline compare))
         (multiple-value-bind (low high)
-            (cond ((csubtypep step-type (specifier-type '(real 0 *)))
-                   (values (numeric-type-low initial-type)
-                           (when (and (numeric-type-p set-type)
-                                      (numeric-type-equal set-type initial-type))
-                             (max* (numeric-type-high initial-type)
-                                   (numeric-type-high set-type)))))
-                  ((csubtypep step-type (specifier-type '(real * 0)))
-                   (values (when (and (numeric-type-p set-type)
-                                      (numeric-type-equal set-type initial-type))
-                             (min* (numeric-type-low initial-type)
-                                   (numeric-type-low set-type)))
-                           (numeric-type-high initial-type)))
-                  (t
-                   (values nil nil)))
+            (let ((step-type-non-negative (csubtypep step-type (specifier-type
+                                                                '(real 0 *))))
+                  (step-type-non-positive (csubtypep step-type (specifier-type
+                                                                '(real * 0)))))
+              (cond ((or (and step-type-non-negative (not minusp))
+                         (and step-type-non-positive minusp))
+                     (values (numeric-type-low initial-type)
+                             (when (and (numeric-type-p set-type)
+                                        (numeric-type-equal set-type initial-type))
+                               (max* (numeric-type-high initial-type)
+                                     (numeric-type-high set-type)))))
+                    ((or (and step-type-non-positive (not minusp))
+                         (and step-type-non-negative minusp))
+                     (values (when (and (numeric-type-p set-type)
+                                        (numeric-type-equal set-type initial-type))
+                               (min* (numeric-type-low initial-type)
+                                     (numeric-type-low set-type)))
+                             (numeric-type-high initial-type)))
+                    (t
+                     (values nil nil))))
           (modified-numeric-type initial-type
                                  :low low
                                  :high high