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b3ecd3b03e
System z branches have a mask to select which of the 4 CC values should cause the branch to be taken. We can invert a branch by inverting the mask. However, not all instructions can produce all 4 CC values, so inverting the branch like this can lead to some oddities. For example, integer comparisons only produce a CC of 0 (equal), 1 (less) or 2 (greater). If an integer EQ is reversed to NE before instruction selection, the branch will test for 1 or 2. If instead the branch is reversed after instruction selection (by inverting the mask), it will test for 1, 2 or 3. Both are correct, but the second isn't really canonical. This patch therefore keeps track of which CC values are possible and uses this when inverting a mask. Although this is mostly cosmestic, it fixes undefined behavior for the CIJNLH in branch-08.ll. Another fix would have been to mask out bit 0 when generating the fused compare and branch, but the point of this patch is that we shouldn't need to do that in the first place. The patch also makes it easier to reuse CC results from other instructions. llvm-svn: 187495
95 lines
2.3 KiB
LLVM
95 lines
2.3 KiB
LLVM
; Test 32-bit atomic subtractions.
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;
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; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z10 | FileCheck %s
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; Check subtraction of a variable.
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define i32 @f1(i32 %dummy, i32 *%src, i32 %b) {
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; CHECK-LABEL: f1:
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; CHECK: l %r2, 0(%r3)
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; CHECK: [[LABEL:\.[^:]*]]:
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; CHECK: lr %r0, %r2
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; CHECK: sr %r0, %r4
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; CHECK: cs %r2, %r0, 0(%r3)
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; CHECK: jl [[LABEL]]
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 %b seq_cst
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ret i32 %res
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}
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; Check subtraction of 1, which can use AHI.
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define i32 @f2(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f2:
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; CHECK: l %r2, 0(%r3)
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; CHECK: [[LABEL:\.[^:]*]]:
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; CHECK: lr %r0, %r2
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; CHECK: ahi %r0, -1
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; CHECK: cs %r2, %r0, 0(%r3)
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; CHECK: jl [[LABEL]]
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 1 seq_cst
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ret i32 %res
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}
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; Check the low end of the AHI range.
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define i32 @f3(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f3:
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; CHECK: ahi %r0, -32768
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 32768 seq_cst
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ret i32 %res
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}
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; Check the next value down, which must use AFI.
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define i32 @f4(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f4:
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; CHECK: afi %r0, -32769
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 32769 seq_cst
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ret i32 %res
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}
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; Check the low end of the AFI range.
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define i32 @f5(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f5:
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; CHECK: afi %r0, -2147483648
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 2147483648 seq_cst
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ret i32 %res
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}
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; Check the next value up, which gets treated as a positive operand.
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define i32 @f6(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f6:
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; CHECK: afi %r0, 2147483647
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 2147483649 seq_cst
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ret i32 %res
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}
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; Check subtraction of -1, which can use AHI.
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define i32 @f7(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f7:
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; CHECK: ahi %r0, 1
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 -1 seq_cst
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ret i32 %res
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}
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; Check the high end of the AHI range.
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define i32 @f8(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f8:
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; CHECK: ahi %r0, 32767
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 -32767 seq_cst
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ret i32 %res
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}
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; Check the next value down, which must use AFI instead.
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define i32 @f9(i32 %dummy, i32 *%src) {
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; CHECK-LABEL: f9:
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; CHECK: afi %r0, 32768
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; CHECK: br %r14
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%res = atomicrmw sub i32 *%src, i32 -32768 seq_cst
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ret i32 %res
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}
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