Add srsh, srsh/immediate instructions

* libguile/vm-engine.c (srsh, srsh/immediate): New instructions.
* module/language/cps/compile-bytecode.scm (compile-function):
* module/language/cps/effects-analysis.scm:
* module/language/cps/reify-primitives.scm (reify-primitives):
* module/language/cps/slot-allocation.scm (compute-var-representations):
* module/language/cps/specialize-primcalls.scm (specialize-primcalls):
* module/language/cps/types.scm (srsh, srsh/immediate):
* module/system/vm/assembler.scm: Add support for new instructions.

* module/language/cps/types.scm (ulsh, ursh): Remove type checkers, as
  these are effect-free.  Limit range of ursh count.

libguile/vm-engine.c

@@ -4068,8 +4068,38 @@ VM_NAME (scm_i_thread *thread, struct scm_vm *vp,
       NEXT (1);
     }
 
-  VM_DEFINE_OP (216, unused_216, NULL, NOP)
-  VM_DEFINE_OP (217, unused_217, NULL, NOP)
+  /* srsh dst:8 a:8 b:8
+   *
+   * Shift the s64 value in A right by B bits, and place the result in
+   * DST.  Only the lower 6 bits of B are used.
+   */
+  VM_DEFINE_OP (216, srsh, "srsh", OP1 (X8_S8_S8_S8) | OP_DST)
+    {
+      scm_t_uint8 dst, a, b;
+
+      UNPACK_8_8_8 (op, dst, a, b);
+
+      SP_SET_S64 (dst, SCM_SRS (SP_REF_S64 (a), (SP_REF_U64 (b) & 63)));
+
+      NEXT (1);
+    }
+
+  /* srsh/immediate dst:8 a:8 b:8
+   *
+   * Shift the s64 value in A right by the immediate B bits, and place
+   * the result in DST.  Only the lower 6 bits of B are used.
+   */
+  VM_DEFINE_OP (217, srsh_immediate, "srsh/immediate", OP1 (X8_S8_S8_C8) | OP_DST)
+    {
+      scm_t_uint8 dst, a, b;
+
+      UNPACK_8_8_8 (op, dst, a, b);
+
+      SP_SET_S64 (dst, SCM_SRS (SP_REF_S64 (a), b & 63));
+
+      NEXT (1);
+    }
+
   VM_DEFINE_OP (218, unused_218, NULL, NOP)
   VM_DEFINE_OP (219, unused_219, NULL, NOP)
   VM_DEFINE_OP (220, unused_220, NULL, NOP)

module/language/cps/compile-bytecode.scm

@@ -202,6 +202,8 @@
          (emit-lsh/immediate asm (from-sp dst) (from-sp (slot x)) y))
         (($ $primcall 'ursh/immediate y (x))
          (emit-ursh/immediate asm (from-sp dst) (from-sp (slot x)) y))
+        (($ $primcall 'srsh/immediate y (x))
+         (emit-srsh/immediate asm (from-sp dst) (from-sp (slot x)) y))
         (($ $primcall 'ulsh/immediate y (x))
          (emit-ulsh/immediate asm (from-sp dst) (from-sp (slot x)) y))
         (($ $primcall 'builtin-ref idx ())

module/language/cps/effects-analysis.scm

@@ -472,8 +472,10 @@ is or might be a read or a write to the same location as A."
   ((ulogxor . _))
   ((ulogsub . _))
   ((ursh . _))
+  ((srsh . _))
   ((ulsh . _))
   ((ursh/immediate . _))
+  ((srsh/immediate . _))
   ((ulsh/immediate . _))
   ((logtest a b)                   &type-check)
   ((logbit? a b)                   &type-check)

module/language/cps/reify-primitives.scm

@@ -199,6 +199,7 @@
               ((rsh/immediate (u6? y) x) (rsh x y))
               ((lsh/immediate (u6? y) x) (lsh x y))
               ((ursh/immediate (u6? y) x) (ursh x y))
+              ((srsh/immediate (u6? y) x) (srsh x y))
               ((ulsh/immediate (u6? y) x) (ulsh x y))
               (_ cps))))))
         (param (error "unexpected param to reified primcall" name))

module/language/cps/slot-allocation.scm

@@ -770,6 +770,7 @@ are comparable with eqv?.  A tmp slot may be used."
               (intmap-add representations var 'u64))
              (($ $primcall (or 'untag-fixnum
                                'scm->s64 'load-s64
+                               'srsh 'srsh/immediate
                                'bv-s8-ref 'bv-s16-ref 'bv-s32-ref 'bv-s64-ref))
               (intmap-add representations var 's64))
              (_

module/language/cps/specialize-primcalls.scm

@@ -74,6 +74,7 @@
         (('umul x (? uint? y)) (umul/immediate y (x)))
         (('umul (? uint? y) x) (umul/immediate y (x)))
         (('ursh x (? uint? y)) (ursh/immediate y (x)))
+        (('srsh x (? uint? y)) (srsh/immediate y (x)))
         (('ulsh x (? uint? y)) (ulsh/immediate y (x)))
         (('scm->f64 (? f64? var)) (load-f64 var ()))
         (('scm->u64 (? u64? var)) (load-u64 var ()))

module/language/cps/types.scm

@@ -1344,17 +1344,31 @@ minimum, and maximum."
                                              (- count) (- count))))
     (define-exact-integer! result min max)))
 
-(define-simple-type-checker (ursh &u64 &u64))
 (define-type-inferrer (ursh a b result)
   (define! result &u64
-    (ash (&min/0 a) (- (&max/u64 b)))
-    (ash (&max/u64 a) (- (&min/0 b)))))
+    (ash (&min/0 a) (- (min 64 (&max/u64 b))))
+    (ash (&max/u64 a) (- (min 64 (&min/0 b))))))
 (define-type-inferrer/param (ursh/immediate param a result)
   (define! result &u64
     (ash (&min/0 a) (- param))
     (ash (&max/u64 a) (- param))))
 
-(define-simple-type-checker (ulsh &u64 &u64))
+(define-type-inferrer (srsh a b result)
+  (let-values (((min max) (compute-ash-range (&min/s64 a)
+                                             (&max/s64 a)
+                                             (- (&min/0 b))
+                                             (- (&max/u64 b)))))
+    (if (<= &s64-min min max &s64-max)
+        (define! result &s64 min max)
+        (define! result &s64 &s64-min &s64-max))))
+(define-type-inferrer/param (srsh/immediate count val result)
+  (let-values (((min max) (compute-ash-range (&min/s64 val)
+                                             (&max/s64 val)
+                                             (- count) (- count))))
+    (if (<= &s64-min min max &s64-max)
+        (define! result &s64 min max)
+        (define! result &s64 &s64-min &s64-max))))
+
 (define-type-inferrer (ulsh a b result)
   (if (and (< (&max/u64 b) 64)
            (<= (ash (&max/u64 a) (&max/u64 b)) &u64-max))

module/system/vm/assembler.scm

@@ -217,8 +217,10 @@
             emit-ulogxor
             emit-ulogsub
             emit-ursh
+            emit-srsh
             emit-ulsh
             emit-ursh/immediate
+            emit-srsh/immediate
             emit-ulsh/immediate
             emit-char->integer
             emit-integer->char