Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp =================================================================== --- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -4877,8 +4877,7 @@ return nullptr; } -static Instruction *foldICmpWithTrunc(ICmpInst &ICmp, - InstCombiner::BuilderTy &Builder) { +Instruction *InstCombinerImpl::foldICmpWithTrunc(ICmpInst &ICmp) { ICmpInst::Predicate Pred = ICmp.getPredicate(); Value *Op0 = ICmp.getOperand(0), *Op1 = ICmp.getOperand(1); @@ -4916,6 +4915,18 @@ return new ICmpInst(ICmpInst::ICMP_EQ, And, MaskC); } + if (auto *II = dyn_cast(X)) { + if (II->getIntrinsicID() == Intrinsic::ctpop || + II->getIntrinsicID() == Intrinsic::cttz || + II->getIntrinsicID() == Intrinsic::ctlz) { + // Make sure the dest bits is enough to save the intrinsic output's range + if (llvm::Log2_32_Ceil(SrcBits) < Op0->getType()->getScalarSizeInBits()) + if (Instruction *I = + foldICmpIntrinsicWithConstant(ICmp, II, C->zext(SrcBits))) + return I; + } + } + return nullptr; } @@ -5073,7 +5084,7 @@ return new ICmpInst(ICmp.getPredicate(), Op0Src, NewOp1); } - if (Instruction *R = foldICmpWithTrunc(ICmp, Builder)) + if (Instruction *R = foldICmpWithTrunc(ICmp)) return R; return foldICmpWithZextOrSext(ICmp); Index: llvm/lib/Transforms/InstCombine/InstCombineInternal.h =================================================================== --- llvm/lib/Transforms/InstCombine/InstCombineInternal.h +++ llvm/lib/Transforms/InstCombine/InstCombineInternal.h @@ -624,6 +624,7 @@ Instruction *foldICmpEqIntrinsicWithConstant(ICmpInst &ICI, IntrinsicInst *II, const APInt &C); Instruction *foldICmpBitCast(ICmpInst &Cmp); + Instruction *foldICmpWithTrunc(ICmpInst &Cmp); // Helpers of visitSelectInst(). Instruction *foldSelectOfBools(SelectInst &SI); Index: llvm/test/Transforms/InstCombine/cmp-intrinsic.ll =================================================================== --- llvm/test/Transforms/InstCombine/cmp-intrinsic.ll +++ llvm/test/Transforms/InstCombine/cmp-intrinsic.ll @@ -540,9 +540,8 @@ define i1 @trunc_cttz_ult_other_i33_i15(i33 %x) { ; CHECK-LABEL: @trunc_cttz_ult_other_i33_i15( -; CHECK-NEXT: [[TZ:%.*]] = tail call i33 @llvm.cttz.i33(i33 [[X:%.*]], i1 false), !range [[RNG1]] -; CHECK-NEXT: [[TRUNC:%.*]] = trunc i33 [[TZ]] to i15 -; CHECK-NEXT: [[CMP:%.*]] = icmp ult i15 [[TRUNC]], 7 +; CHECK-NEXT: [[TMP1:%.*]] = and i33 [[X:%.*]], 127 +; CHECK-NEXT: [[CMP:%.*]] = icmp ne i33 [[TMP1]], 0 ; CHECK-NEXT: ret i1 [[CMP]] ; %tz = tail call i33 @llvm.cttz.i33(i33 %x, i1 false) @@ -575,9 +574,7 @@ define i1 @trunc_ctlz_ugt_other_i32(i32 %x) { ; CHECK-LABEL: @trunc_ctlz_ugt_other_i32( -; CHECK-NEXT: [[LZ:%.*]] = tail call i32 @llvm.ctlz.i32(i32 [[X:%.*]], i1 false), !range [[RNG0]] -; CHECK-NEXT: [[TRUNC:%.*]] = trunc i32 [[LZ]] to i15 -; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i15 [[TRUNC]], 4 +; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[X:%.*]], 134217728 ; CHECK-NEXT: ret i1 [[CMP]] ; %lz = tail call i32 @llvm.ctlz.i32(i32 %x, i1 false)