[PhaseOrdering] add tests for bittest patterns from bitfields; NFC

As mentioned in D45986, there's a potential ordering dependency 
between instcombine and aggressive-instcombine for detecting these,
so I'm adding a few tests to confirm that the expected folds occur
using -O3 (because aggressive-instcombine only runs at -O3 currently).

llvm-svn: 331308

1 files changed, 152 insertions, 0 deletions

diff --git a/llvm/test/Transforms/PhaseOrdering/bitfield-bittests.ll b/llvm/test/Transforms/PhaseOrdering/bitfield-bittests.ll
new file mode 100644
index 00000000000..59bb9457734
--- /dev/null
+++ b/llvm/test/Transforms/PhaseOrdering/bitfield-bittests.ll
@@ -0,0 +1,152 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -O3 -S < %s                    | FileCheck %s
+; RUN: opt -passes='default<O3>' -S < %s  | FileCheck %s
+
+; These are tests that check for set/clear bits in a bitfield based on PR37098:
+; https://bugs.llvm.org/show_bug.cgi?id=37098
+;
+; The initial IR from clang has been transformed by SROA, but no other passes
+; have run yet. In all cases, we should reduce these to a mask and compare
+; instead of shift/cast/logic ops.
+;
+; Currently, this happens mostly through a combination of instcombine and
+; aggressive-instcombine. If pass ordering changes, we may have to adjust
+; the pattern matching in 1 or both of those passes.
+
+; Legal i32 is required to allow casting transforms that eliminate the zexts.
+target datalayout = "n32"
+
+define i32 @allclear(i32 %a) {
+; CHECK-LABEL: @allclear(
+; CHECK-NEXT:    [[BF_LSHR:%.*]] = lshr i32 [[A:%.*]], 1
+; CHECK-NEXT:    [[BF_CLEAR1:%.*]] = or i32 [[BF_LSHR]], [[A]]
+; CHECK-NEXT:    [[BF_LSHR5:%.*]] = lshr i32 [[A]], 2
+; CHECK-NEXT:    [[OR2:%.*]] = or i32 [[BF_CLEAR1]], [[BF_LSHR5]]
+; CHECK-NEXT:    [[BF_LSHR10:%.*]] = lshr i32 [[A]], 3
+; CHECK-NEXT:    [[OR83:%.*]] = or i32 [[OR2]], [[BF_LSHR10]]
+; CHECK-NEXT:    [[OR13:%.*]] = and i32 [[OR83]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[OR13]], 1
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a.sroa.0.0.trunc = trunc i32 %a to i8
+  %a.sroa.5.0.shift = lshr i32 %a, 8
+  %bf.clear = and i8 %a.sroa.0.0.trunc, 1
+  %bf.cast = zext i8 %bf.clear to i32
+  %bf.lshr = lshr i8 %a.sroa.0.0.trunc, 1
+  %bf.clear2 = and i8 %bf.lshr, 1
+  %bf.cast3 = zext i8 %bf.clear2 to i32
+  %or = or i32 %bf.cast, %bf.cast3
+  %bf.lshr5 = lshr i8 %a.sroa.0.0.trunc, 2
+  %bf.clear6 = and i8 %bf.lshr5, 1
+  %bf.cast7 = zext i8 %bf.clear6 to i32
+  %or8 = or i32 %or, %bf.cast7
+  %bf.lshr10 = lshr i8 %a.sroa.0.0.trunc, 3
+  %bf.clear11 = and i8 %bf.lshr10, 1
+  %bf.cast12 = zext i8 %bf.clear11 to i32
+  %or13 = or i32 %or8, %bf.cast12
+  %cmp = icmp eq i32 %or13, 0
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+}
+
+define i32 @anyset(i32 %a) {
+; CHECK-LABEL: @anyset(
+; CHECK-NEXT:    [[BF_LSHR:%.*]] = lshr i32 [[A:%.*]], 1
+; CHECK-NEXT:    [[BF_CLEAR1:%.*]] = or i32 [[BF_LSHR]], [[A]]
+; CHECK-NEXT:    [[BF_LSHR5:%.*]] = lshr i32 [[A]], 2
+; CHECK-NEXT:    [[OR2:%.*]] = or i32 [[BF_CLEAR1]], [[BF_LSHR5]]
+; CHECK-NEXT:    [[BF_LSHR10:%.*]] = lshr i32 [[A]], 3
+; CHECK-NEXT:    [[OR83:%.*]] = or i32 [[OR2]], [[BF_LSHR10]]
+; CHECK-NEXT:    [[OR13:%.*]] = and i32 [[OR83]], 1
+; CHECK-NEXT:    ret i32 [[OR13]]
+;
+  %a.sroa.0.0.trunc = trunc i32 %a to i8
+  %a.sroa.5.0.shift = lshr i32 %a, 8
+  %bf.clear = and i8 %a.sroa.0.0.trunc, 1
+  %bf.cast = zext i8 %bf.clear to i32
+  %bf.lshr = lshr i8 %a.sroa.0.0.trunc, 1
+  %bf.clear2 = and i8 %bf.lshr, 1
+  %bf.cast3 = zext i8 %bf.clear2 to i32
+  %or = or i32 %bf.cast, %bf.cast3
+  %bf.lshr5 = lshr i8 %a.sroa.0.0.trunc, 2
+  %bf.clear6 = and i8 %bf.lshr5, 1
+  %bf.cast7 = zext i8 %bf.clear6 to i32
+  %or8 = or i32 %or, %bf.cast7
+  %bf.lshr10 = lshr i8 %a.sroa.0.0.trunc, 3
+  %bf.clear11 = and i8 %bf.lshr10, 1
+  %bf.cast12 = zext i8 %bf.clear11 to i32
+  %or13 = or i32 %or8, %bf.cast12
+  %cmp = icmp ne i32 %or13, 0
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+}
+
+; FIXME: aggressive-instcombine does not match this yet.
+
+define i32 @allset(i32 %a) {
+; CHECK-LABEL: @allset(
+; CHECK-NEXT:    [[BF_LSHR:%.*]] = lshr i32 [[A:%.*]], 1
+; CHECK-NEXT:    [[BF_LSHR5:%.*]] = lshr i32 [[A]], 2
+; CHECK-NEXT:    [[BF_LSHR10:%.*]] = lshr i32 [[A]], 3
+; CHECK-NEXT:    [[BF_CLEAR2:%.*]] = and i32 [[A]], 1
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[BF_CLEAR2]], [[BF_LSHR]]
+; CHECK-NEXT:    [[AND8:%.*]] = and i32 [[AND]], [[BF_LSHR5]]
+; CHECK-NEXT:    [[AND13:%.*]] = and i32 [[AND8]], [[BF_LSHR10]]
+; CHECK-NEXT:    ret i32 [[AND13]]
+;
+  %a.sroa.0.0.trunc = trunc i32 %a to i8
+  %a.sroa.5.0.shift = lshr i32 %a, 8
+  %bf.clear = and i8 %a.sroa.0.0.trunc, 1
+  %bf.cast = zext i8 %bf.clear to i32
+  %bf.lshr = lshr i8 %a.sroa.0.0.trunc, 1
+  %bf.clear2 = and i8 %bf.lshr, 1
+  %bf.cast3 = zext i8 %bf.clear2 to i32
+  %and = and i32 %bf.cast, %bf.cast3
+  %bf.lshr5 = lshr i8 %a.sroa.0.0.trunc, 2
+  %bf.clear6 = and i8 %bf.lshr5, 1
+  %bf.cast7 = zext i8 %bf.clear6 to i32
+  %and8 = and i32 %and, %bf.cast7
+  %bf.lshr10 = lshr i8 %a.sroa.0.0.trunc, 3
+  %bf.clear11 = and i8 %bf.lshr10, 1
+  %bf.cast12 = zext i8 %bf.clear11 to i32
+  %and13 = and i32 %and8, %bf.cast12
+  %cmp = icmp ne i32 %and13, 0
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+}
+
+; FIXME: aggressive-instcombine does not match this yet.
+
+define i32 @anyclear(i32 %a) {
+; CHECK-LABEL: @anyclear(
+; CHECK-NEXT:    [[BF_LSHR:%.*]] = lshr i32 [[A:%.*]], 1
+; CHECK-NEXT:    [[BF_LSHR5:%.*]] = lshr i32 [[A]], 2
+; CHECK-NEXT:    [[BF_LSHR10:%.*]] = lshr i32 [[A]], 3
+; CHECK-NEXT:    [[BF_CLEAR2:%.*]] = and i32 [[A]], 1
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[BF_CLEAR2]], [[BF_LSHR]]
+; CHECK-NEXT:    [[AND8:%.*]] = and i32 [[AND]], [[BF_LSHR5]]
+; CHECK-NEXT:    [[AND13:%.*]] = and i32 [[AND8]], [[BF_LSHR10]]
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[AND13]], 1
+; CHECK-NEXT:    ret i32 [[TMP1]]
+;
+  %a.sroa.0.0.trunc = trunc i32 %a to i8
+  %a.sroa.5.0.shift = lshr i32 %a, 8
+  %bf.clear = and i8 %a.sroa.0.0.trunc, 1
+  %bf.cast = zext i8 %bf.clear to i32
+  %bf.lshr = lshr i8 %a.sroa.0.0.trunc, 1
+  %bf.clear2 = and i8 %bf.lshr, 1
+  %bf.cast3 = zext i8 %bf.clear2 to i32
+  %and = and i32 %bf.cast, %bf.cast3
+  %bf.lshr5 = lshr i8 %a.sroa.0.0.trunc, 2
+  %bf.clear6 = and i8 %bf.lshr5, 1
+  %bf.cast7 = zext i8 %bf.clear6 to i32
+  %and8 = and i32 %and, %bf.cast7
+  %bf.lshr10 = lshr i8 %a.sroa.0.0.trunc, 3
+  %bf.clear11 = and i8 %bf.lshr10, 1
+  %bf.cast12 = zext i8 %bf.clear11 to i32
+  %and13 = and i32 %and8, %bf.cast12
+  %cmp = icmp eq i32 %and13, 0
+  %conv = zext i1 %cmp to i32
+  ret i32 %conv
+}
+