diff options
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstSimplify/compare.ll | 11 |
2 files changed, 20 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index bd42af15da3..1054c7935b5 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1964,7 +1964,15 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, APInt Val = CI2->getValue().abs(); if (!Val.isMinValue()) { Lower = IntMin.sdiv(Val); - Upper = IntMax.sdiv(Val) + 1; + APInt Rem; + APInt::sdivrem(IntMax, Val, Upper, Rem); + // We may need to round the result of the INT_MAX / CI2 calculation up + // if we see that the division was not exact. + if (Rem.isMinValue()) + Upper = Upper + 1; + else + Upper = Upper + 2; + assert(Upper != Lower && "Upper part of range has wrapped!"); } } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) { // 'lshr x, CI2' produces [0, UINT_MAX >> CI2]. diff --git a/llvm/test/Transforms/InstSimplify/compare.ll b/llvm/test/Transforms/InstSimplify/compare.ll index 7d0cd9c5878..d329b7b719f 100644 --- a/llvm/test/Transforms/InstSimplify/compare.ll +++ b/llvm/test/Transforms/InstSimplify/compare.ll @@ -913,3 +913,14 @@ define i1 @icmp_sdiv_int_min(i32 %a) { ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[DIV]], -1073741824 ; CHECK-NEXT: ret i1 [[CMP]] } + +define i1 @icmp_sdiv_pr20288(i64 %a) { + %div = sdiv i64 %a, -8589934592 + %cmp = icmp ne i64 %div, 1073741824 + ret i1 %cmp + +; CHECK-LABEL: @icmp_sdiv_pr20288 +; CHECK-NEXT: [[DIV:%.*]] = sdiv i64 %a, -8589934592 +; CHECK-NEXT: [[CMP:%.*]] = icmp ne i64 [[DIV]], 1073741824 +; CHECK-NEXT: ret i1 [[CMP]] +} |
