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author | Sanjay Patel <spatel@rotateright.com> | 2020-02-10 15:10:47 -0500 |
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committer | Hans Wennborg <hans@chromium.org> | 2020-03-19 10:02:25 +0100 |
commit | cfa792458fc47f9890d94a2718288c269c8a2a6e (patch) | |
tree | ca52daf37e8fb4eb2b979d641c9bb5f4dad9844b | |
parent | 52c365aa9ca071dbd0d220463b2c4f8e21642b36 (diff) | |
download | llvm-cfa792458fc47f9890d94a2718288c269c8a2a6e.zip llvm-cfa792458fc47f9890d94a2718288c269c8a2a6e.tar.gz llvm-cfa792458fc47f9890d94a2718288c269c8a2a6e.tar.bz2 |
[Transforms] add phase ordering tests for min/max/abs; NFC
Test that instcombine and early-cse can cooperate
to reduce sequences of select patterns that are not
composed of the same underlying instructions.
There's a bug in EarlyCSE (PR41083), and we can test
how much a possible fix (D74285) may affect optimization.
(cherry picked from commit 0ad6e726ec7eee8ef14a89fa288d5a1420d96b1e)
-rw-r--r-- | llvm/test/Transforms/PhaseOrdering/min-max-abs-cse.ll | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/llvm/test/Transforms/PhaseOrdering/min-max-abs-cse.ll b/llvm/test/Transforms/PhaseOrdering/min-max-abs-cse.ll new file mode 100644 index 0000000..fcdbbbf --- /dev/null +++ b/llvm/test/Transforms/PhaseOrdering/min-max-abs-cse.ll @@ -0,0 +1,87 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt < %s -S -O1 | FileCheck %s +; RUN: opt -passes='default<O1>' -S < %s | FileCheck %s + +; In all tests, expect instcombine to canonicalize the select patterns +; for min/max/abs to allow CSE and subsequent simplification. + +; sub (smax a,b), (smax a,b) --> 0 + +define i8 @smax_nsw(i8 %a, i8 %b) { +; CHECK-LABEL: @smax_nsw( +; CHECK-NEXT: ret i8 0 +; + %sub = sub nsw i8 %a, %b + %cmp1 = icmp slt i8 %a, %b + %cmp2 = icmp sgt i8 %sub, 0 + %m1 = select i1 %cmp1, i8 0, i8 %sub + %m2 = select i1 %cmp2, i8 %sub, i8 0 + %r = sub i8 %m2, %m1 + ret i8 %r +} + +; or (abs a), (abs a) --> abs a + +define i8 @abs_swapped(i8 %a) { +; CHECK-LABEL: @abs_swapped( +; CHECK-NEXT: [[NEG:%.*]] = sub i8 0, [[A:%.*]] +; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i8 [[A]], 0 +; CHECK-NEXT: [[M1:%.*]] = select i1 [[CMP1]], i8 [[NEG]], i8 [[A]] +; CHECK-NEXT: ret i8 [[M1]] +; + %neg = sub i8 0, %a + %cmp1 = icmp sgt i8 %a, 0 + %cmp2 = icmp slt i8 %a, 0 + %m1 = select i1 %cmp1, i8 %a, i8 %neg + %m2 = select i1 %cmp2, i8 %neg, i8 %a + %r = or i8 %m2, %m1 + ret i8 %r +} + +; xor (nabs a), (nabs a) --> 0 + +define i8 @nabs_swapped(i8 %a) { +; CHECK-LABEL: @nabs_swapped( +; CHECK-NEXT: ret i8 0 +; + %neg = sub i8 0, %a + %cmp1 = icmp slt i8 %a, 0 + %cmp2 = icmp sgt i8 %a, 0 + %m1 = select i1 %cmp1, i8 %a, i8 %neg + %m2 = select i1 %cmp2, i8 %neg, i8 %a + %r = xor i8 %m2, %m1 + ret i8 %r +} + +; xor (abs a), (abs a) --> 0 + +define i8 @abs_different_constants(i8 %a) { +; CHECK-LABEL: @abs_different_constants( +; CHECK-NEXT: ret i8 0 +; + %neg = sub i8 0, %a + %cmp1 = icmp sgt i8 %a, -1 + %cmp2 = icmp slt i8 %a, 0 + %m1 = select i1 %cmp1, i8 %a, i8 %neg + %m2 = select i1 %cmp2, i8 %neg, i8 %a + %r = xor i8 %m2, %m1 + ret i8 %r +} + +; or (nabs a), (nabs a) --> nabs a + +define i8 @nabs_different_constants(i8 %a) { +; CHECK-LABEL: @nabs_different_constants( +; CHECK-NEXT: [[NEG:%.*]] = sub i8 0, [[A:%.*]] +; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i8 [[A]], 0 +; CHECK-NEXT: [[M1:%.*]] = select i1 [[CMP1]], i8 [[A]], i8 [[NEG]] +; CHECK-NEXT: ret i8 [[M1]] +; + %neg = sub i8 0, %a + %cmp1 = icmp slt i8 %a, 0 + %cmp2 = icmp sgt i8 %a, -1 + %m1 = select i1 %cmp1, i8 %a, i8 %neg + %m2 = select i1 %cmp2, i8 %neg, i8 %a + %r = or i8 %m2, %m1 + ret i8 %r +} |