Author: Nikita Popov Date: 2020-12-13T21:00:32+01:00 New Revision: 22dba707b0fbf778466baef718cc536700b99df3
URL: https://github.com/llvm/llvm-project/commit/22dba707b0fbf778466baef718cc536700b99df3 DIFF: https://github.com/llvm/llvm-project/commit/22dba707b0fbf778466baef718cc536700b99df3.diff LOG: [AC] Handle (X+C1)<C2 assumes (PR48408) InstCombine canonicalizes X>C && X<C' style comparisons into (X+C1)<C2. This type of expression is recognized by some analyses like LVI, but currently not when used inside assumptions, because AssumptionCache does not track affected values for it. Added: Modified: llvm/lib/Analysis/AssumptionCache.cpp llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll Removed: ################################################################################ diff --git a/llvm/lib/Analysis/AssumptionCache.cpp b/llvm/lib/Analysis/AssumptionCache.cpp index fdde5eac16b7..cb94f716bdb3 100644 --- a/llvm/lib/Analysis/AssumptionCache.cpp +++ b/llvm/lib/Analysis/AssumptionCache.cpp @@ -115,6 +115,14 @@ findAffectedValues(CallInst *CI, AddAffectedFromEq(A); AddAffectedFromEq(B); } + + Value *X; + // Handle (A + C1) u< C2, which is the canonical form of A > C3 && A < C4, + // and recognized by LVI at least. + if (Pred == ICmpInst::ICMP_ULT && + match(A, m_Add(m_Value(X), m_ConstantInt())) && + match(B, m_ConstantInt())) + AddAffected(X); } } diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll b/llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll index 71cdbefc8942..b1e3bd334d91 100644 --- a/llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll +++ b/llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll @@ -577,9 +577,8 @@ define i1 @test_assume_cmp_with_offset(i64 %idx) { ; CHECK-NEXT: [[IDX_OFF1:%.*]] = add i64 [[IDX:%.*]], -5 ; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i64 [[IDX_OFF1]], 3 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP1]]) -; CHECK-NEXT: [[IDX_OFF2:%.*]] = add i64 [[IDX]], -1 -; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i64 [[IDX_OFF2]], 10 -; CHECK-NEXT: ret i1 [[CMP2]] +; CHECK-NEXT: [[IDX_OFF2:%.*]] = add nsw i64 [[IDX]], -1 +; CHECK-NEXT: ret i1 true ; %idx.off1 = add i64 %idx, -5 %cmp1 = icmp ult i64 %idx.off1, 3 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
