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no-op weak.py reorder [PR] (#17646)

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chenyu
2026-08-20 23:56:06 -04:00
committed by GitHub
parent d716d0d927
commit 1bcb6bdc62
1 changed files with 21 additions and 18 deletions
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tinygrad/uop/weak.py
+21 -18
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@@ -11,12 +11,24 @@ def commit_weak(s:UOp, dt:DType) -> UOp:
# a CONST commits directly at dt (the value stays mathematical, emission truncates), a non-const src takes the cast
return UOp.const(s.val, dt) if s.op is Ops.CONST else s.cast(dt)
def commit_weak_srcs(u:UOp) -> UOp|None:
if not any(s.dtype in dtypes.weaks for s in u.src): return None
if (dt:=least_upper_dtype(*(s.dtype for s in u.src))) in dtypes.weaks: return None
def commit_srcs_at(u:UOp, dt:DType) -> UOp:
# the root re-derives: a shift's dtype is its lhs's, so committing the lhs commits the node too
return u.replace(dtype=None, src=tuple(commit_weak(s, dt) if s.dtype in dtypes.weaks else s for s in u.src))
def commit_weak_srcs(u:UOp) -> UOp|None:
if not any(s.dtype in dtypes.weaks for s in u.src) or (dt:=least_upper_dtype(*(s.dtype for s in u.src))) in dtypes.weaks: return None
return commit_srcs_at(u, dt)
# a concrete CAST over a weak node states the width the value will live at. that width is a floor, never a narrowing
def cast_weak_srcs(c:UOp, u:UOp) -> UOp|None:
if c.dtype in dtypes.weaks or weak_dtype(c.dtype) is not u.dtype: return None
return commit_srcs_at(u, least_upper_dtype(c.dtype, default_dtype(u))).cast(c.dtype)
pm_cast_weak = PatternMatcher([
(UPat(Ops.CAST, name="c", src=(UPat(GroupOp.ALU, dtype=dtypes.weaks, name="u"),)), cast_weak_srcs),
(UPat(Ops.CAST, name="c", src=(UPat(Ops.CONST, dtype=dtypes.weaks, name="u"),)), lambda c,u: commit_weak(u, c.dtype)),
])
# runs in index lowering and in the decomps: a rule that mints a weak const commits it in the same rewrite, so none reaches the renderer
pm_commit_weak = PatternMatcher([
(UPat(GroupOp.Broadcastable, name="u"), commit_weak_srcs),
@@ -25,20 +37,13 @@ pm_commit_weak = PatternMatcher([
lambda u: u.replace(src=(u.src[0], commit_weak(u.src[1], u.src[0].dtype), *u.src[2:]))),
])
# a concrete CAST over a weak node states the width the value will live at. that width is a floor, never a narrowing
def cast_weak_srcs(c:UOp, u:UOp) -> UOp|None:
if c.dtype in dtypes.weaks or weak_dtype(c.dtype) is not u.dtype: return None
dt = least_upper_dtype(c.dtype, default_dtype(u))
return u.replace(dtype=None, src=tuple(commit_weak(s, dt) if s.dtype in dtypes.weaks else s for s in u.src)).cast(c.dtype)
pm_cast_weak = PatternMatcher([
(UPat(Ops.CAST, name="c", src=(UPat(GroupOp.ALU, dtype=dtypes.weaks, name="u"),)), cast_weak_srcs),
(UPat(Ops.CAST, name="c", src=(UPat(Ops.CONST, dtype=dtypes.weaks, name="u"),)), lambda c,u: commit_weak(u, c.dtype)),
])
# A weakfloat Unary (sin/exp2/...) must resolve here, before the transcendental decomposition.
_lower_weak_ops = GroupOp.Binary|GroupOp.Unary|{Ops.WHERE, Ops.RANGE, Ops.STACK, Ops.SPECIAL}
def lower_weak_node(u:UOp) -> UOp|None:
start, src = (1 if u.op is Ops.WHERE else 0), tuple(s.src[0] if s.op is Ops.CAST and s.dtype in dtypes.weaks else s for s in u.src)
src = tuple(s.src[0] if s.op is Ops.CAST and s.dtype in dtypes.weaks else s for s in u.src)
start = 1 if u.op is Ops.WHERE else 0 # WHERE's cond is bool, never part of the width unification
if src == u.src or any(s.dtype in dtypes.weaks for s in src[start:]): return None
# Binary can widen from the bounds, all other nodes derive from the lowered sources.
dt = strong_dtype(least_upper_dtype(default_dtype(u), *(s.dtype for s in src)) if u.op in GroupOp.Binary
else unwrap(dtype_from_uop(u.op, src, u.arg)))
return u.replace(dtype=None, src=src[:start]+tuple(s if s.base.is_invalid else commit_weak(s, dt) for s in src[start:])).cast(u.dtype)
@@ -49,11 +54,9 @@ pm_lower_weak = PatternMatcher([
# a SINGLE weak cast is never rewritten here, each consumer absorbs it on its own edge (see lower_weak_srcs)
(UPat(Ops.CAST, dtype=dtypes.weaks, src=(UPat(Ops.CAST, dtype=dtypes.weaks, src=(UPat.var("x"),)),), name="u"),
lambda u,x: x.cast(default_dtype(u.src[0])).cast(default_dtype(u)).cast(u.dtype) if x.dtype not in dtypes.weaks else None),
# Binary can widen from the bounds, all other nodes derive from the lowered sources.
# a weakfloat Unary (sin/exp2/...) must resolve here, before the transcendental decomposition
(UPat(GroupOp.Binary|GroupOp.Unary|{Ops.WHERE, Ops.RANGE, Ops.STACK, Ops.SPECIAL}, name="u"), lower_weak_node),
(UPat((Ops.PARAM, Ops.BUFFER), dtype=dtypes.weakint, name="u"),
lambda u: u.replace(dtype=None, arg=replace(u.arg, dtype=default_dtype(u))).cast(dtypes.weakint) if u.addrspace == AddrSpace.ALU else None),
(UPat(_lower_weak_ops, name="u"), lower_weak_node),
])
def lower_weak_srcs(ctx:dict[UOp, UOp]|None, u:UOp) -> UOp|None: