llvm/test/CodeGen/SystemZ/Large/branch-range-01.py

   1 # Test normal conditional branches 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 #   0xffd8 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 8 bytes if it uses a short branch
  21 # and 10 if it uses a long one.  The ones before "main:" have to take the branch
  22 # length into account -- which is 4 bytes for short branches -- so the final
  23 # (0x28 - 4) / 8 == 4 blocks can use short branches.  The ones after "main:"
  24 # do not, so the first 0x28 / 8 == 5 can use short branches.  However,
  25 # the conservative algorithm we use makes one branch unnecessarily long
  26 # on each side.
  27 #
  28 # CHECK: c %r4, 0(%r3)
  29 # CHECK: jge [[LABEL:\.L[^ ]*]]
  30 # CHECK: c %r4, 4(%r3)
  31 # CHECK: jge [[LABEL]]
  32 # CHECK: c %r4, 8(%r3)
  33 # CHECK: jge [[LABEL]]
  34 # CHECK: c %r4, 12(%r3)
  35 # CHECK: jge [[LABEL]]
  36 # CHECK: c %r4, 16(%r3)
  37 # CHECK: jge [[LABEL]]
  38 # CHECK: c %r4, 20(%r3)
  39 # CHECK: jge [[LABEL]]
  40 # CHECK: c %r4, 24(%r3)
  41 # CHECK: j{{g?}}e [[LABEL]]
  42 # CHECK: c %r4, 28(%r3)
  43 # CHECK: je [[LABEL]]
  44 # CHECK: c %r4, 32(%r3)
  45 # CHECK: je [[LABEL]]
  46 # CHECK: c %r4, 36(%r3)
  47 # CHECK: je [[LABEL]]
  48 # ...main goes here...
  49 # CHECK: c %r4, 100(%r3)
  50 # CHECK: je [[LABEL:\.L[^ ]*]]
  51 # CHECK: c %r4, 104(%r3)
  52 # CHECK: je [[LABEL]]
  53 # CHECK: c %r4, 108(%r3)
  54 # CHECK: je [[LABEL]]
  55 # CHECK: c %r4, 112(%r3)
  56 # CHECK: je [[LABEL]]
  57 # CHECK: c %r4, 116(%r3)
  58 # CHECK: j{{g?}}e [[LABEL]]
  59 # CHECK: c %r4, 120(%r3)
  60 # CHECK: jge [[LABEL]]
  61 # CHECK: c %r4, 124(%r3)
  62 # CHECK: jge [[LABEL]]
  63 # CHECK: c %r4, 128(%r3)
  64 # CHECK: jge [[LABEL]]
  65 # CHECK: c %r4, 132(%r3)
  66 # CHECK: jge [[LABEL]]
  67 # CHECK: c %r4, 136(%r3)
  68 # CHECK: jge [[LABEL]]
  69
  70 from __future__ import print_function
  71
  72 branch_blocks = 10
  73 main_size = 0xFFD8
  74
  75 print("@global = global i32 0")
  76
  77 print("define void @f1(i8 *%base, i32 *%stop, i32 %limit) {")
  78 print("entry:")
  79 print("  br label %before0")
  80 print("")
  81
  82 for i in range(branch_blocks):
  83     next = "before%d" % (i + 1) if i + 1 < branch_blocks else "main"
  84     print("before%d:" % i)
  85     print("  %%bstop%d = getelementptr i32, i32 *%%stop, i64 %d" % (i, i))
  86     print("  %%bcur%d = load i32 , i32 *%%bstop%d" % (i, i))
  87     print("  %%btest%d = icmp eq i32 %%limit, %%bcur%d" % (i, i))
  88     print("  br i1 %%btest%d, label %%after0, label %%%s" % (i, next))
  89     print("")
  90
  91 print("%s:" % next)
  92 a, b = 1, 1
  93 for i in range(0, main_size, 6):
  94     a, b = b, a + b
  95     offset = 4096 + b % 500000
  96     value = a % 256
  97     print("  %%ptr%d = getelementptr i8, i8 *%%base, i64 %d" % (i, offset))
  98     print("  store volatile i8 %d, i8 *%%ptr%d" % (value, i))
  99
 100 for i in range(branch_blocks):
 101     print("  %%astop%d = getelementptr i32, i32 *%%stop, i64 %d" % (i, i + 25))
 102     print("  %%acur%d = load i32 , i32 *%%astop%d" % (i, i))
 103     print("  %%atest%d = icmp eq i32 %%limit, %%acur%d" % (i, i))
 104     print("  br i1 %%atest%d, label %%main, label %%after%d" % (i, i))
 105     print("")
 106     print("after%d:" % i)
 107
 108 print("  %dummy = load volatile i32, i32 *@global")
 109 print("  ret void")
 110 print("}")