Teach the peepholer to fold unary operations on constants.
Afterwards, -0.5 loads in a single step and no longer requires a runtime
UNARY_NEGATIVE operation.
diff --git a/Lib/test/test_peepholer.py b/Lib/test/test_peepholer.py
index 34bd99f..4385a84 100644
--- a/Lib/test/test_peepholer.py
+++ b/Lib/test/test_peepholer.py
@@ -133,6 +133,25 @@
asm = dis_single('a="x"*1000')
self.assert_('(1000)' in asm)
+ def test_folding_of_unaryops_on_constants(self):
+ for line, elem in (
+ ('`1`', "('1')"), # unary convert
+ ('-0.5', '(-0.5)'), # unary negative
+ ('~-2', '(1)'), # unary invert
+ ):
+ asm = dis_single(line)
+ self.assert_(elem in asm, asm)
+ self.assert_('UNARY_' not in asm)
+
+ # Verify that unfoldables are skipped
+ for line, elem in (
+ ('-"abc"', "('abc')"), # unary negative
+ ('~"abc"', "('abc')"), # unary invert
+ ):
+ asm = dis_single(line)
+ self.assert_(elem in asm, asm)
+ self.assert_('UNARY_' in asm)
+
def test_elim_extra_return(self):
# RETURN LOAD_CONST None RETURN --> RETURN
def f(x):