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https://github.com/c64scene-ar/llvm-6502.git
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6824f127f9
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187495 91177308-0d34-0410-b5e6-96231b3b80d8
133 lines
3.8 KiB
LLVM
133 lines
3.8 KiB
LLVM
; Test 8-bit atomic subtractions.
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;
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; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s -check-prefix=CHECK
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; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s -check-prefix=CHECK-SHIFT1
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; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s -check-prefix=CHECK-SHIFT2
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; Check subtraction of a variable.
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; - CHECK is for the main loop.
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; - CHECK-SHIFT1 makes sure that the negated shift count used by the second
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; RLL is set up correctly. The negation is independent of the NILL and L
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; tested in CHECK.
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; - CHECK-SHIFT2 makes sure that %b is shifted into the high part of the word
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; before being used. This shift is independent of the other loop prologue
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; instructions.
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define i8 @f1(i8 *%src, i8 %b) {
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; CHECK-LABEL: f1:
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; CHECK: sllg [[SHIFT:%r[1-9]+]], %r2, 3
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; CHECK: nill %r2, 65532
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; CHECK: l [[OLD:%r[0-9]+]], 0(%r2)
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; CHECK: [[LABEL:\.[^:]*]]:
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; CHECK: rll [[ROT:%r[0-9]+]], [[OLD]], 0([[SHIFT]])
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; CHECK: sr [[ROT]], %r3
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; CHECK: rll [[NEW:%r[0-9]+]], [[ROT]], 0({{%r[1-9]+}})
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; CHECK: cs [[OLD]], [[NEW]], 0(%r2)
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; CHECK: jl [[LABEL]]
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; CHECK: rll %r2, [[OLD]], 8([[SHIFT]])
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f1:
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; CHECK-SHIFT1: sllg [[SHIFT:%r[1-9]+]], %r2, 3
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; CHECK-SHIFT1: lcr [[NEGSHIFT:%r[1-9]+]], [[SHIFT]]
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; CHECK-SHIFT1: rll
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; CHECK-SHIFT1: rll {{%r[0-9]+}}, {{%r[0-9]+}}, 0([[NEGSHIFT]])
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; CHECK-SHIFT1: rll
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; CHECK-SHIFT1: br %r14
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;
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; CHECK-SHIFT2-LABEL: f1:
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; CHECK-SHIFT2: sll %r3, 24
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; CHECK-SHIFT2: rll
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; CHECK-SHIFT2: sr {{%r[0-9]+}}, %r3
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; CHECK-SHIFT2: rll
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; CHECK-SHIFT2: rll
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 %b seq_cst
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ret i8 %res
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}
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; Check the minimum signed value. We add 0x80000000 to the rotated word.
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define i8 @f2(i8 *%src) {
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; CHECK-LABEL: f2:
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; CHECK: sllg [[SHIFT:%r[1-9]+]], %r2, 3
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; CHECK: nill %r2, 65532
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; CHECK: l [[OLD:%r[0-9]+]], 0(%r2)
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; CHECK: [[LABEL:\.[^:]*]]:
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; CHECK: rll [[ROT:%r[0-9]+]], [[OLD]], 0([[SHIFT]])
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; CHECK: afi [[ROT]], -2147483648
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; CHECK: rll [[NEW:%r[0-9]+]], [[ROT]], 0([[NEGSHIFT:%r[1-9]+]])
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; CHECK: cs [[OLD]], [[NEW]], 0(%r2)
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; CHECK: jl [[LABEL]]
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; CHECK: rll %r2, [[OLD]], 8([[SHIFT]])
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f2:
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; CHECK-SHIFT1: sllg [[SHIFT:%r[1-9]+]], %r2, 3
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; CHECK-SHIFT1: lcr [[NEGSHIFT:%r[1-9]+]], [[SHIFT]]
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; CHECK-SHIFT1: rll
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; CHECK-SHIFT1: rll {{%r[0-9]+}}, {{%r[0-9]+}}, 0([[NEGSHIFT]])
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; CHECK-SHIFT1: rll
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; CHECK-SHIFT1: br %r14
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;
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; CHECK-SHIFT2-LABEL: f2:
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 -128 seq_cst
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ret i8 %res
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}
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; Check subtraction of -1. We add 0x01000000 to the rotated word.
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define i8 @f3(i8 *%src) {
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; CHECK-LABEL: f3:
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; CHECK: afi [[ROT]], 16777216
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f3:
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; CHECK-SHIFT1: br %r14
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; CHECK-SHIFT2-LABEL: f3:
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 -1 seq_cst
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ret i8 %res
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}
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; Check subtraction of -1. We add 0xff000000 to the rotated word.
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define i8 @f4(i8 *%src) {
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; CHECK-LABEL: f4:
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; CHECK: afi [[ROT]], -16777216
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f4:
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; CHECK-SHIFT1: br %r14
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; CHECK-SHIFT2-LABEL: f4:
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 1 seq_cst
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ret i8 %res
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}
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; Check the maximum signed value. We add 0x81000000 to the rotated word.
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define i8 @f5(i8 *%src) {
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; CHECK-LABEL: f5:
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; CHECK: afi [[ROT]], -2130706432
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f5:
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; CHECK-SHIFT1: br %r14
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; CHECK-SHIFT2-LABEL: f5:
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 127 seq_cst
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ret i8 %res
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}
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; Check subtraction of a large unsigned value. We add 0x02000000 to the
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; rotated word.
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define i8 @f6(i8 *%src) {
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; CHECK-LABEL: f6:
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; CHECK: afi [[ROT]], 33554432
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; CHECK: br %r14
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;
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; CHECK-SHIFT1-LABEL: f6:
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; CHECK-SHIFT1: br %r14
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; CHECK-SHIFT2-LABEL: f6:
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; CHECK-SHIFT2: br %r14
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%res = atomicrmw sub i8 *%src, i8 254 seq_cst
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ret i8 %res
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}
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