diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 13 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/icmp.ll | 20 |
2 files changed, 33 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 9ce1c3fc41b..dbf43f7769c 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -3490,6 +3490,19 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { } } } + + if (BO0) { + // Transform A & (L - 1) `ult` L --> L != 0 + Value *L; + auto LSubOne = m_Add(m_Value(L), m_AllOnes()); + auto BitwiseAnd = + m_CombineOr(m_And(m_Value(), LSubOne), m_And(LSubOne, m_Value())); + + if (match(BO0, BitwiseAnd) && I.getPredicate() == ICmpInst::ICMP_ULT) { + auto *Zero = Constant::getNullValue(BO0->getType()); + return new ICmpInst(ICmpInst::ICMP_NE, L, Zero); + } + } } { Value *A, *B; diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll index edcf76d5a7d..5d97411625e 100644 --- a/llvm/test/Transforms/InstCombine/icmp.ll +++ b/llvm/test/Transforms/InstCombine/icmp.ll @@ -1603,3 +1603,23 @@ define i32 @f7(i32 %a, i32 %b) { %s = select i1 %cmp, i32 10000, i32 0 ret i32 %s } + +; CHECK: @f8( +; CHECK-NEXT: [[RESULT:%[a-z0-9]+]] = icmp ne i32 %lim, 0 +; CHECK-NEXT: ret i1 [[RESULT]] +define i1 @f8(i32 %val, i32 %lim) { + %lim.sub = add i32 %lim, -1 + %val.and = and i32 %val, %lim.sub + %r = icmp ult i32 %val.and, %lim + ret i1 %r +} + +; CHECK: @f9( +; CHECK-NEXT: [[RESULT:%[a-z0-9]+]] = icmp ne i32 %lim, 0 +; CHECK-NEXT: ret i1 [[RESULT]] +define i1 @f9(i32 %val, i32 %lim) { + %lim.sub = sub i32 %lim, 1 + %val.and = and i32 %val, %lim.sub + %r = icmp ult i32 %val.and, %lim + ret i1 %r +} |
