llvm/test/CodeGen/SystemZ/Large/branch-range-08.py

# Test 64-bit BRANCH RELATIVE ON COUNT in cases where some branches are out
# of range.
# RUN: python %s | llc -mtriple=s390x-linux-gnu | FileCheck %s

# Construct:
#
# loopN:
#   load of countN
#   ...
# loop0:
#   0xffd8 bytes, from MVIY instructions
#   conditional branch to main
# after0:
#   ...
#   decrement of countN
#   conditional branch to loopN
# afterN:
#
# Each load occupies 6 bytes.  Each decrement and branch occupies 4
# bytes if BRCTG can be used, otherwise it occupies 10 bytes (AGHI + BRCL).
# This means that loop 5 contains 4 * 6 + 0xffd8 + 4 * 4 == 0x10000 bytes
# and is therefore (just) in range.  Loop 6 is out of range.
#
# CHECK: brctg {{%r[0-9]+}}
# CHECK: brctg {{%r[0-9]+}}
# CHECK: brctg {{%r[0-9]+}}
# CHECK: brctg {{%r[0-9]+}}
# CHECK: brctg {{%r[0-9]+}}
# CHECK: aghi {{%r[0-9]+}}, -1
# CHECK: jglh
# CHECK: aghi {{%r[0-9]+}}, -1
# CHECK: jglh
# CHECK: aghi {{%r[0-9]+}}, -1
# CHECK: jglh

branch_blocks = 8
main_size = 0xffd8

print 'define void @f1(i8 *%base, i64 *%counts) {'
print 'entry:'

for i in xrange(branch_blocks - 1, -1, -1):
    print '  %%countptr%d = getelementptr i64, i64 *%%counts, i64 %d' % (i, i)
    print '  %%initcount%d = load i64 , i64 *%%countptr%d' % (i, i)
    print '  br label %%loop%d' % i
    
    print 'loop%d:' % i
    block1 = 'entry' if i == branch_blocks - 1 else 'loop%d' % (i + 1)
    block2 = 'loop0' if i == 0 else 'after%d' % (i - 1)
    print ('  %%count%d = phi i64 [ %%initcount%d, %%%s ],'
           ' [ %%nextcount%d, %%%s ]' % (i, i, block1, i, block2))

a, b = 1, 1
for i in xrange(0, main_size, 6):
    a, b = b, a + b
    offset = 4096 + b % 500000
    value = a % 256
    print '  %%ptr%d = getelementptr i8, i8 *%%base, i64 %d' % (i, offset)
    print '  store volatile i8 %d, i8 *%%ptr%d' % (value, i)

for i in xrange(branch_blocks):
    print '  %%nextcount%d = add i64 %%count%d, -1' % (i, i)
    print '  %%test%d = icmp ne i64 %%nextcount%d, 0' % (i, i)
    print '  br i1 %%test%d, label %%loop%d, label %%after%d' % (i, i, i)
    print ''
    print 'after%d:' % i

print '  ret void'
print '}'