test/CodeGen/SystemZ/Large/branch-range-04.py

   1 # Test 64-bit COMPARE AND BRANCH in cases where the sheer number of
   2 # instructions causes some branches to be out of range.
   3 # RUN: python %s | llc -mtriple=s390x-linux-gnu | FileCheck %s
   4
   5 # Construct:
   6 #
   7 # before0:
   8 #   conditional branch to after0
   9 #   ...
  10 # beforeN:
  11 #   conditional branch to after0
  12 # main:
  13 #   0xffcc bytes, from MVIY instructions
  14 #   conditional branch to main
  15 # after0:
  16 #   ...
  17 #   conditional branch to main
  18 # afterN:
  19 #
  20 # Each conditional branch sequence occupies 12 bytes if it uses a short
  21 # branch and 16 if it uses a long one.  The ones before "main:" have to
  22 # take the branch length into account, which is 6 for short branches,
  23 # so the final (0x34 - 6) / 12 == 3 blocks can use short branches.
  24 # The ones after "main:" do not, so the first 0x34 / 12 == 4 blocks
  25 # can use short branches.  The conservative algorithm we use makes
  26 # one of the forward branches unnecessarily long, as noted in the
  27 # check output below.
  28 #
  29 # CHECK: lgb [[REG:%r[0-5]]], 0(%r3)
  30 # CHECK: cgr %r4, [[REG]]
  31 # CHECK: jge [[LABEL:\.L[^ ]*]]
  32 # CHECK: lgb [[REG:%r[0-5]]], 1(%r3)
  33 # CHECK: cgr %r4, [[REG]]
  34 # CHECK: jge [[LABEL]]
  35 # CHECK: lgb [[REG:%r[0-5]]], 2(%r3)
  36 # CHECK: cgr %r4, [[REG]]
  37 # CHECK: jge [[LABEL]]
  38 # CHECK: lgb [[REG:%r[0-5]]], 3(%r3)
  39 # CHECK: cgr %r4, [[REG]]
  40 # CHECK: jge [[LABEL]]
  41 # CHECK: lgb [[REG:%r[0-5]]], 4(%r3)
  42 # CHECK: cgr %r4, [[REG]]
  43 # CHECK: jge [[LABEL]]
  44 # ...as mentioned above, the next one could be a CGRJE instead...
  45 # CHECK: lgb [[REG:%r[0-5]]], 5(%r3)
  46 # CHECK: cgr %r4, [[REG]]
  47 # CHECK: jge [[LABEL]]
  48 # CHECK: lgb [[REG:%r[0-5]]], 6(%r3)
  49 # CHECK: cgrje %r4, [[REG]], [[LABEL]]
  50 # CHECK: lgb [[REG:%r[0-5]]], 7(%r3)
  51 # CHECK: cgrje %r4, [[REG]], [[LABEL]]
  52 # ...main goes here...
  53 # CHECK: lgb [[REG:%r[0-5]]], 25(%r3)
  54 # CHECK: cgrje %r4, [[REG]], [[LABEL:\.L[^ ]*]]
  55 # CHECK: lgb [[REG:%r[0-5]]], 26(%r3)
  56 # CHECK: cgrje %r4, [[REG]], [[LABEL]]
  57 # CHECK: lgb [[REG:%r[0-5]]], 27(%r3)
  58 # CHECK: cgrje %r4, [[REG]], [[LABEL]]
  59 # CHECK: lgb [[REG:%r[0-5]]], 28(%r3)
  60 # CHECK: cgrje %r4, [[REG]], [[LABEL]]
  61 # CHECK: lgb [[REG:%r[0-5]]], 29(%r3)
  62 # CHECK: cgr %r4, [[REG]]
  63 # CHECK: jge [[LABEL]]
  64 # CHECK: lgb [[REG:%r[0-5]]], 30(%r3)
  65 # CHECK: cgr %r4, [[REG]]
  66 # CHECK: jge [[LABEL]]
  67 # CHECK: lgb [[REG:%r[0-5]]], 31(%r3)
  68 # CHECK: cgr %r4, [[REG]]
  69 # CHECK: jge [[LABEL]]
  70 # CHECK: lgb [[REG:%r[0-5]]], 32(%r3)
  71 # CHECK: cgr %r4, [[REG]]
  72 # CHECK: jge [[LABEL]]
  73
  74 from __future__ import print_function
  75
  76 branch_blocks = 8
  77 main_size = 0xffcc
  78
  79 print('@global = global i32 0')
  80
  81 print('define void @f1(i8 *%base, i8 *%stop, i64 %limit) {')
  82 print('entry:')
  83 print('  br label %before0')
  84 print('')
  85
  86 for i in range(branch_blocks):
  87     next = 'before%d' % (i + 1) if i + 1 < branch_blocks else 'main'
  88     print('before%d:' % i)
  89     print('  %%bstop%d = getelementptr i8, i8 *%%stop, i64 %d' % (i, i))
  90     print('  %%bcur%d = load i8 , i8 *%%bstop%d' % (i, i))
  91     print('  %%bext%d = sext i8 %%bcur%d to i64' % (i, i))
  92     print('  %%btest%d = icmp eq i64 %%limit, %%bext%d' % (i, i))
  93     print('  br i1 %%btest%d, label %%after0, label %%%s' % (i, next))
  94     print('')
  95
  96 print('%s:' % next)
  97 a, b = 1, 1
  98 for i in range(0, main_size, 6):
  99     a, b = b, a + b
 100     offset = 4096 + b % 500000
 101     value = a % 256
 102     print('  %%ptr%d = getelementptr i8, i8 *%%base, i64 %d' % (i, offset))
 103     print('  store volatile i8 %d, i8 *%%ptr%d' % (value, i))
 104
 105 for i in range(branch_blocks):
 106     print('  %%astop%d = getelementptr i8, i8 *%%stop, i64 %d' % (i, i + 25))
 107     print('  %%acur%d = load i8 , i8 *%%astop%d' % (i, i))
 108     print('  %%aext%d = sext i8 %%acur%d to i64' % (i, i))
 109     print('  %%atest%d = icmp eq i64 %%limit, %%aext%d' % (i, i))
 110     print('  br i1 %%atest%d, label %%main, label %%after%d' % (i, i))
 111     print('')
 112     print('after%d:' % i)
 113
 114 print('  %dummy = load volatile i32, i32 *@global')
 115 print('  ret void')
 116 print('}')