llvm/test/CodeGen/SystemZ/Large/branch-range-11.py

   1 # Test 32-bit COMPARE LOGICAL IMMEDIATE AND BRANCH in cases where the sheer
   2 # number of 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 #   0xffc6 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 14 bytes if it uses a short
  21 # branch and 20 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 (0x3a - 6) / 14 == 3 blocks can use short branches.
  24 # The ones after "main:" do not, so the first 0x3a / 14 == 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: l [[REG:%r[0-5]]], 0(%r3)
  30 # CHECK: s [[REG]], 0(%r4)
  31 # CHECK: clfi [[REG]], 50
  32 # CHECK: jgl [[LABEL:\.L[^ ]*]]
  33 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  34 # CHECK: s [[REG]], 0(%r4)
  35 # CHECK: clfi [[REG]], 51
  36 # CHECK: jgl [[LABEL]]
  37 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  38 # CHECK: s [[REG]], 0(%r4)
  39 # CHECK: clfi [[REG]], 52
  40 # CHECK: jgl [[LABEL]]
  41 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  42 # CHECK: s [[REG]], 0(%r4)
  43 # CHECK: clfi [[REG]], 53
  44 # CHECK: jgl [[LABEL]]
  45 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  46 # CHECK: s [[REG]], 0(%r4)
  47 # CHECK: clfi [[REG]], 54
  48 # CHECK: jgl [[LABEL]]
  49 # ...as mentioned above, the next one could be a CLIJL instead...
  50 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  51 # CHECK: s [[REG]], 0(%r4)
  52 # CHECK: clfi [[REG]], 55
  53 # CHECK: jgl [[LABEL]]
  54 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  55 # CHECK: s [[REG]], 0(%r4)
  56 # CHECK: clijl [[REG]], 56, [[LABEL]]
  57 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  58 # CHECK: s [[REG]], 0(%r4)
  59 # CHECK: clijl [[REG]], 57, [[LABEL]]
  60 # ...main goes here...
  61 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  62 # CHECK: s [[REG]], 0(%r4)
  63 # CHECK: clijl [[REG]], 100, [[LABEL:\.L[^ ]*]]
  64 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  65 # CHECK: s [[REG]], 0(%r4)
  66 # CHECK: clijl [[REG]], 101, [[LABEL]]
  67 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  68 # CHECK: s [[REG]], 0(%r4)
  69 # CHECK: clijl [[REG]], 102, [[LABEL]]
  70 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  71 # CHECK: s [[REG]], 0(%r4)
  72 # CHECK: clijl [[REG]], 103, [[LABEL]]
  73 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  74 # CHECK: s [[REG]], 0(%r4)
  75 # CHECK: clfi [[REG]], 104
  76 # CHECK: jgl [[LABEL]]
  77 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  78 # CHECK: s [[REG]], 0(%r4)
  79 # CHECK: clfi [[REG]], 105
  80 # CHECK: jgl [[LABEL]]
  81 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  82 # CHECK: s [[REG]], 0(%r4)
  83 # CHECK: clfi [[REG]], 106
  84 # CHECK: jgl [[LABEL]]
  85 # CHECK: l [[REG:%r[0-5]]], 0(%r3)
  86 # CHECK: s [[REG]], 0(%r4)
  87 # CHECK: clfi [[REG]], 107
  88 # CHECK: jgl [[LABEL]]
  89
  90 from __future__ import print_function
  91
  92 branch_blocks = 8
  93 main_size = 0xFFC6
  94
  95 print("@global = global i32 0")
  96
  97 print("define void @f1(i8 *%base, i32 *%stopa, i32 *%stopb) {")
  98 print("entry:")
  99 print("  br label %before0")
 100 print("")
 101
 102 for i in range(branch_blocks):
 103     next = "before%d" % (i + 1) if i + 1 < branch_blocks else "main"
 104     print("before%d:" % i)
 105     print("  %%bcur%da = load i32 , i32 *%%stopa" % i)
 106     print("  %%bcur%db = load i32 , i32 *%%stopb" % i)
 107     print("  %%bsub%d = sub i32 %%bcur%da, %%bcur%db" % (i, i, i))
 108     print("  %%btest%d = icmp ult i32 %%bsub%d, %d" % (i, i, i + 50))
 109     print("  br i1 %%btest%d, label %%after0, label %%%s" % (i, next))
 110     print("")
 111
 112 print("%s:" % next)
 113 a, b = 1, 1
 114 for i in range(0, main_size, 6):
 115     a, b = b, a + b
 116     offset = 4096 + b % 500000
 117     value = a % 256
 118     print("  %%ptr%d = getelementptr i8, i8 *%%base, i64 %d" % (i, offset))
 119     print("  store volatile i8 %d, i8 *%%ptr%d" % (value, i))
 120
 121 for i in range(branch_blocks):
 122     print("  %%acur%da = load i32 , i32 *%%stopa" % i)
 123     print("  %%acur%db = load i32 , i32 *%%stopb" % i)
 124     print("  %%asub%d = sub i32 %%acur%da, %%acur%db" % (i, i, i))
 125     print("  %%atest%d = icmp ult i32 %%asub%d, %d" % (i, i, i + 100))
 126     print("  br i1 %%atest%d, label %%main, label %%after%d" % (i, i))
 127     print("")
 128     print("after%d:" % i)
 129
 130 print("  %dummy = load volatile i32, i32 *@global")
 131 print("  ret void")
 132 print("}")