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https://github.com/c64scene-ar/llvm-6502.git
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086791eca2
One unusual feature of the z architecture is that the result of a previous load can be reused indefinitely for subsequent loads, even if a cache-coherent store to that location is performed by another CPU. A special serializing instruction must be used if you want to force a load to be reattempted. Since volatile loads are not supposed to be omitted in this way, we should insert a serializing instruction before each such load. The same goes for atomic loads. The patch implements this at the IR->DAG boundary, in a similar way to atomic fences. It is a no-op for targets other than SystemZ. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196905 91177308-0d34-0410-b5e6-96231b3b80d8
106 lines
3.0 KiB
Python
106 lines
3.0 KiB
Python
# Test normal conditional branches in cases where the sheer number of
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# instructions causes some branches to be out of range.
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# RUN: python %s | llc -mtriple=s390x-linux-gnu | FileCheck %s
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# Construct:
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#
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# before0:
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# conditional branch to after0
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# ...
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# beforeN:
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# conditional branch to after0
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# main:
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# 0xffd8 bytes, from MVIY instructions
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# conditional branch to main
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# after0:
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# ...
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# conditional branch to main
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# afterN:
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#
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# Each conditional branch sequence occupies 8 bytes if it uses a short branch
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# and 10 if it uses a long one. The ones before "main:" have to take the branch
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# length into account -- which is 4 bytes for short branches -- so the final
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# (0x28 - 4) / 8 == 4 blocks can use short branches. The ones after "main:"
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# do not, so the first 0x28 / 8 == 5 can use short branches. However,
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# the conservative algorithm we use makes one branch unnecessarily long
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# on each side.
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#
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# CHECK: c %r4, 0(%r3)
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# CHECK: jge [[LABEL:\.L[^ ]*]]
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# CHECK: c %r4, 4(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 8(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 12(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 16(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 20(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 24(%r3)
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# CHECK: j{{g?}}e [[LABEL]]
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# CHECK: c %r4, 28(%r3)
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# CHECK: je [[LABEL]]
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# CHECK: c %r4, 32(%r3)
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# CHECK: je [[LABEL]]
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# CHECK: c %r4, 36(%r3)
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# CHECK: je [[LABEL]]
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# ...main goes here...
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# CHECK: c %r4, 100(%r3)
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# CHECK: je [[LABEL:\.L[^ ]*]]
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# CHECK: c %r4, 104(%r3)
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# CHECK: je [[LABEL]]
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# CHECK: c %r4, 108(%r3)
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# CHECK: je [[LABEL]]
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# CHECK: c %r4, 112(%r3)
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# CHECK: je [[LABEL]]
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# CHECK: c %r4, 116(%r3)
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# CHECK: j{{g?}}e [[LABEL]]
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# CHECK: c %r4, 120(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 124(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 128(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 132(%r3)
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# CHECK: jge [[LABEL]]
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# CHECK: c %r4, 136(%r3)
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# CHECK: jge [[LABEL]]
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branch_blocks = 10
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main_size = 0xffd8
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print 'define void @f1(i8 *%base, i32 *%stop, i32 %limit) {'
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print 'entry:'
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print ' br label %before0'
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print ''
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for i in xrange(branch_blocks):
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next = 'before%d' % (i + 1) if i + 1 < branch_blocks else 'main'
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print 'before%d:' % i
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print ' %%bstop%d = getelementptr i32 *%%stop, i64 %d' % (i, i)
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print ' %%bcur%d = load i32 *%%bstop%d' % (i, i)
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print ' %%btest%d = icmp eq i32 %%limit, %%bcur%d' % (i, i)
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print ' br i1 %%btest%d, label %%after0, label %%%s' % (i, next)
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print ''
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print '%s:' % next
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a, b = 1, 1
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for i in xrange(0, main_size, 6):
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a, b = b, a + b
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offset = 4096 + b % 500000
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value = a % 256
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print ' %%ptr%d = getelementptr i8 *%%base, i64 %d' % (i, offset)
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print ' store volatile i8 %d, i8 *%%ptr%d' % (value, i)
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for i in xrange(branch_blocks):
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print ' %%astop%d = getelementptr i32 *%%stop, i64 %d' % (i, i + 25)
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print ' %%acur%d = load i32 *%%astop%d' % (i, i)
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print ' %%atest%d = icmp eq i32 %%limit, %%acur%d' % (i, i)
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print ' br i1 %%atest%d, label %%main, label %%after%d' % (i, i)
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print ''
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print 'after%d:' % i
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print ' ret void'
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print '}'
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