Backport r69961 to trunk, replacing JUMP_IF_{TRUE,FALSE} with
POP_JUMP_IF_{TRUE,FALSE} and JUMP_IF_{TRUE,FALSE}_OR_POP. This avoids executing
a POP_TOP on each conditional and sometimes allows the peephole optimizer to
skip a JUMP_ABSOLUTE entirely. It speeds up list comprehensions significantly.
diff --git a/Lib/compiler/pycodegen.py b/Lib/compiler/pycodegen.py
index 6d5a41c..81234d1 100644
--- a/Lib/compiler/pycodegen.py
+++ b/Lib/compiler/pycodegen.py
@@ -421,13 +421,11 @@
self.set_lineno(test)
self.visit(test)
nextTest = self.newBlock()
- self.emit('JUMP_IF_FALSE', nextTest)
+ self.emit('POP_JUMP_IF_FALSE', nextTest)
self.nextBlock()
- self.emit('POP_TOP')
self.visit(suite)
self.emit('JUMP_FORWARD', end)
self.startBlock(nextTest)
- self.emit('POP_TOP')
if node.else_:
self.visit(node.else_)
self.nextBlock(end)
@@ -446,15 +444,13 @@
self.set_lineno(node, force=True)
self.visit(node.test)
- self.emit('JUMP_IF_FALSE', else_ or after)
+ self.emit('POP_JUMP_IF_FALSE', else_ or after)
self.nextBlock()
- self.emit('POP_TOP')
self.visit(node.body)
self.emit('JUMP_ABSOLUTE', loop)
self.startBlock(else_) # or just the POPs if not else clause
- self.emit('POP_TOP')
self.emit('POP_BLOCK')
self.setups.pop()
if node.else_:
@@ -525,26 +521,23 @@
self.visit(child)
self.emit(jump, end)
self.nextBlock()
- self.emit('POP_TOP')
self.visit(node.nodes[-1])
self.nextBlock(end)
def visitAnd(self, node):
- self.visitTest(node, 'JUMP_IF_FALSE')
+ self.visitTest(node, 'JUMP_IF_FALSE_OR_POP')
def visitOr(self, node):
- self.visitTest(node, 'JUMP_IF_TRUE')
+ self.visitTest(node, 'JUMP_IF_TRUE_OR_POP')
def visitIfExp(self, node):
endblock = self.newBlock()
elseblock = self.newBlock()
self.visit(node.test)
- self.emit('JUMP_IF_FALSE', elseblock)
- self.emit('POP_TOP')
+ self.emit('POP_JUMP_IF_FALSE', elseblock)
self.visit(node.then)
self.emit('JUMP_FORWARD', endblock)
self.nextBlock(elseblock)
- self.emit('POP_TOP')
self.visit(node.else_)
self.nextBlock(endblock)
@@ -556,9 +549,8 @@
self.emit('DUP_TOP')
self.emit('ROT_THREE')
self.emit('COMPARE_OP', op)
- self.emit('JUMP_IF_FALSE', cleanup)
+ self.emit('JUMP_IF_FALSE_OR_POP', cleanup)
self.nextBlock()
- self.emit('POP_TOP')
# now do the last comparison
if node.ops:
op, code = node.ops[-1]
@@ -593,11 +585,7 @@
for start, cont, anchor in stack:
if cont:
- skip_one = self.newBlock()
- self.emit('JUMP_FORWARD', skip_one)
- self.startBlock(cont)
- self.emit('POP_TOP')
- self.nextBlock(skip_one)
+ self.nextBlock(cont)
self.emit('JUMP_ABSOLUTE', start)
self.startBlock(anchor)
@@ -617,9 +605,8 @@
def visitListCompIf(self, node, branch):
self.set_lineno(node, force=True)
self.visit(node.test)
- self.emit('JUMP_IF_FALSE', branch)
+ self.emit('POP_JUMP_IF_FALSE', branch)
self.newBlock()
- self.emit('POP_TOP')
def _makeClosure(self, gen, args):
frees = gen.scope.get_free_vars()
@@ -665,11 +652,7 @@
for start, cont, anchor, end in stack:
if cont:
- skip_one = self.newBlock()
- self.emit('JUMP_FORWARD', skip_one)
- self.startBlock(cont)
- self.emit('POP_TOP')
- self.nextBlock(skip_one)
+ self.nextBlock(cont)
self.emit('JUMP_ABSOLUTE', start)
self.startBlock(anchor)
self.emit('POP_BLOCK')
@@ -702,9 +685,8 @@
def visitGenExprIf(self, node, branch):
self.set_lineno(node, force=True)
self.visit(node.test)
- self.emit('JUMP_IF_FALSE', branch)
+ self.emit('POP_JUMP_IF_FALSE', branch)
self.newBlock()
- self.emit('POP_TOP')
# exception related
@@ -719,9 +701,8 @@
# is a sort of renaming op.
self.nextBlock()
self.visit(node.test)
- self.emit('JUMP_IF_TRUE', end)
+ self.emit('POP_JUMP_IF_TRUE', end)
self.nextBlock()
- self.emit('POP_TOP')
self.emit('LOAD_GLOBAL', 'AssertionError')
if node.fail:
self.visit(node.fail)
@@ -729,7 +710,6 @@
else:
self.emit('RAISE_VARARGS', 1)
self.nextBlock(end)
- self.emit('POP_TOP')
def visitRaise(self, node):
self.set_lineno(node)
@@ -772,9 +752,8 @@
self.visit(expr)
self.emit('COMPARE_OP', 'exception match')
next = self.newBlock()
- self.emit('JUMP_IF_FALSE', next)
+ self.emit('POP_JUMP_IF_FALSE', next)
self.nextBlock()
- self.emit('POP_TOP')
self.emit('POP_TOP')
if target:
self.visit(target)
@@ -787,8 +766,6 @@
self.nextBlock(next)
else:
self.nextBlock()
- if expr: # XXX
- self.emit('POP_TOP')
self.emit('END_FINALLY')
if node.else_:
self.nextBlock(lElse)