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 branch_blocks = 8 75 main_size = 0xffcc 76 77 print 'define void @f1(i8 *%base, i8 *%stop, i64 %limit) {' 78 print 'entry:' 79 print ' br label %before0' 80 print '' 81 82 for i in xrange(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 i8, i8 *%%stop, i64 %d' % (i, i) 86 print ' %%bcur%d = load i8 , i8 *%%bstop%d' % (i, i) 87 print ' %%bext%d = sext i8 %%bcur%d to i64' % (i, i) 88 print ' %%btest%d = icmp eq i64 %%limit, %%bext%d' % (i, i) 89 print ' br i1 %%btest%d, label %%after0, label %%%s' % (i, next) 90 print '' 91 92 print '%s:' % next 93 a, b = 1, 1 94 for i in xrange(0, main_size, 6): 95 a, b = b, a + b 96 offset = 4096 + b % 500000 97 value = a % 256 98 print ' %%ptr%d = getelementptr i8, i8 *%%base, i64 %d' % (i, offset) 99 print ' store volatile i8 %d, i8 *%%ptr%d' % (value, i) 100 101 for i in xrange(branch_blocks): 102 print ' %%astop%d = getelementptr i8, i8 *%%stop, i64 %d' % (i, i + 25) 103 print ' %%acur%d = load i8 , i8 *%%astop%d' % (i, i) 104 print ' %%aext%d = sext i8 %%acur%d to i64' % (i, i) 105 print ' %%atest%d = icmp eq i64 %%limit, %%aext%d' % (i, i) 106 print ' br i1 %%atest%d, label %%main, label %%after%d' % (i, i) 107 print '' 108 print 'after%d:' % i 109 110 print ' ret void' 111 print '}' 112
