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| author | Roman Lebedev <lebedev.ri@gmail.com> | 2018-12-03 20:07:58 +0000 |
|---|---|---|
| committer | Roman Lebedev <lebedev.ri@gmail.com> | 2018-12-03 20:07:58 +0000 |
| commit | 7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5 (patch) | |
| tree | 5418846be3447317399c9598f12f0c2744f84db8 | |
| parent | f75f88d090c46a7fd9da3c966678e19f2c301a55 (diff) | |
| download | bcm5719-llvm-7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5.tar.gz bcm5719-llvm-7bf2fed16773b549f9abf6cdaa4b42f2f2644ed5.zip | |
[InstCombine] foldICmpWithLowBitMaskedVal(): disable 2 faulty folds.
These two folds are invalid for this non-constant pattern
when the mask ends up being all-ones:
https://rise4fun.com/Alive/9au
https://rise4fun.com/Alive/UcQM
Fixes https://bugs.llvm.org/show_bug.cgi?id=39861
llvm-svn: 348181
3 files changed, 16 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 2ba1174517f..ab933d7d961 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2955,12 +2955,16 @@ static Value *foldICmpWithLowBitMaskedVal(ICmpInst &I, // x & (-1 >> y) s>= x -> x s<= (-1 >> y) if (X != I.getOperand(1)) // X must be on RHS of comparison! return nullptr; // Ignore the other case. + if (!match(M, m_Constant())) // Can not do this fold with non-constant. + return nullptr; DstPred = ICmpInst::Predicate::ICMP_SLE; break; case ICmpInst::Predicate::ICMP_SLT: // x & (-1 >> y) s< x -> x s> (-1 >> y) if (X != I.getOperand(1)) // X must be on RHS of comparison! return nullptr; // Ignore the other case. + if (!match(M, m_Constant())) // Can not do this fold with non-constant. + return nullptr; DstPred = ICmpInst::Predicate::ICMP_SGT; break; case ICmpInst::Predicate::ICMP_SLE: diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-sge-to-icmp-sle.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-sge-to-icmp-sle.ll index 7be784a452f..502b015b122 100644 --- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-sge-to-icmp-sle.ll +++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-sge-to-icmp-sle.ll @@ -26,8 +26,9 @@ define i1 @p0(i8 %x) { define i1 @pv(i8 %x, i8 %y) { ; CHECK-LABEL: @pv( ; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] -; CHECK-NEXT: [[TMP1:%.*]] = icmp sge i8 [[TMP0]], [[X:%.*]] -; CHECK-NEXT: ret i1 [[TMP1]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[TMP0]], [[X:%.*]] +; CHECK-NEXT: [[RET:%.*]] = icmp sge i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] ; %tmp0 = lshr i8 -1, %y %tmp1 = and i8 %tmp0, %x @@ -120,8 +121,9 @@ define i1 @cv0(i8 %y) { ; CHECK-LABEL: @cv0( ; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() ; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] -; CHECK-NEXT: [[TMP1:%.*]] = icmp sle i8 [[X]], [[TMP0]] -; CHECK-NEXT: ret i1 [[TMP1]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], [[TMP0]] +; CHECK-NEXT: [[RET:%.*]] = icmp sge i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] ; %x = call i8 @gen8() %tmp0 = lshr i8 -1, %y diff --git a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll index d1792d1e075..7daa043e801 100644 --- a/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll +++ b/llvm/test/Transforms/InstCombine/canonicalize-constant-low-bit-mask-and-icmp-slt-to-icmp-sgt.ll @@ -26,8 +26,9 @@ define i1 @p0(i8 %x) { define i1 @pv(i8 %x, i8 %y) { ; CHECK-LABEL: @pv( ; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] -; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i8 [[TMP0]], [[X:%.*]] -; CHECK-NEXT: ret i1 [[TMP1]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[TMP0]], [[X:%.*]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] ; %tmp0 = lshr i8 -1, %y %tmp1 = and i8 %tmp0, %x @@ -120,8 +121,9 @@ define i1 @cv0(i8 %y) { ; CHECK-LABEL: @cv0( ; CHECK-NEXT: [[X:%.*]] = call i8 @gen8() ; CHECK-NEXT: [[TMP0:%.*]] = lshr i8 -1, [[Y:%.*]] -; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i8 [[X]], [[TMP0]] -; CHECK-NEXT: ret i1 [[TMP1]] +; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], [[TMP0]] +; CHECK-NEXT: [[RET:%.*]] = icmp slt i8 [[TMP1]], [[X]] +; CHECK-NEXT: ret i1 [[RET]] ; %x = call i8 @gen8() %tmp0 = lshr i8 -1, %y |
