diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -1631,7 +1631,16 @@ // Returns true if \p I is an instruction that will be predicated either // through scalar predication or masked load/store or masked gather/scatter. // Superset of instructions that return true for isScalarWithPredication. - bool isPredicatedInst(Instruction *I) { + bool isPredicatedInst(Instruction *I, bool IsKnownUniform = false) { + // When we know the load is uniform and the original scalar loop was not + // predicated we don't need to mark it as a predicated instruction. Any + // vectorised blocks created when tail-folding are something artificial we + // have introduced and we know there is always at least one active lane. + // That's why we call Legal->blockNeedsPredication here because it doesn't + // query tail-folding. + if (IsKnownUniform && isa(I) && + !Legal->blockNeedsPredication(I->getParent())) + return false; if (!blockNeedsPredicationForAnyReason(I->getParent())) return false; // Loads and stores that need some form of masked operation are predicated @@ -9180,7 +9189,8 @@ Range); bool IsPredicated = LoopVectorizationPlanner::getDecisionAndClampRange( - [&](ElementCount VF) { return CM.isPredicatedInst(I); }, Range); + [&](ElementCount VF) { return CM.isPredicatedInst(I, IsUniform); }, + Range); // Even if the instruction is not marked as uniform, there are certain // intrinsic calls that can be effectively treated as such, so we check for diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/tail-fold-uniform-memops.ll b/llvm/test/Transforms/LoopVectorize/AArch64/tail-fold-uniform-memops.ll --- a/llvm/test/Transforms/LoopVectorize/AArch64/tail-fold-uniform-memops.ll +++ b/llvm/test/Transforms/LoopVectorize/AArch64/tail-fold-uniform-memops.ll @@ -5,54 +5,28 @@ target triple = "aarch64-linux-gnu" +; The original loop had an unconditional uniform load. Let's make sure +; we don't artificially create new predicated blocks for the load. define void @uniform_load(i32* noalias %dst, i32* noalias readonly %src, i64 %n) #0 { ; CHECK-LABEL: @uniform_load( ; CHECK: vector.body: -; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %vector.ph ], [ [[INDEX_NEXT:%.*]], %pred.load.continue8 ] -; CHECK-NEXT: [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <4 x i64> poison, i64 [[INDEX]], i32 0 -; CHECK-NEXT: [[BROADCAST_SPLAT2:%.*]] = shufflevector <4 x i64> [[BROADCAST_SPLATINSERT1]], <4 x i64> poison, <4 x i32> zeroinitializer -; CHECK-NEXT: [[INDUCTION:%.*]] = add <4 x i64> [[BROADCAST_SPLAT2]], -; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[INDEX]], 0 -; CHECK-NEXT: [[TMP1:%.*]] = icmp ule <4 x i64> [[INDUCTION]] -; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i1> [[TMP1]], i32 0 -; CHECK-NEXT: br i1 [[TMP2]], label [[PRED_LOAD_IF:%.*]], label %pred.load.continue -; CHECK: pred.load.if: -; CHECK-NEXT: [[TMP3:%.*]] = load i32, i32* [[SRC:%.*]], align 4 -; CHECK-NEXT: [[TMP4:%.*]] = insertelement <4 x i32> poison, i32 [[TMP3]], i32 0 -; CHECK-NEXT: br label %pred.load.continue -; CHECK: pred.load.continue: -; CHECK-NEXT: [[TMP5:%.*]] = phi <4 x i32> [ poison, %vector.body ], [ [[TMP4]], [[PRED_LOAD_IF]] ] -; CHECK-NEXT: [[TMP6:%.*]] = extractelement <4 x i1> [[TMP1]], i32 1 -; CHECK-NEXT: br i1 [[TMP6]], label [[PRED_LOAD_IF3:%.*]], label %pred.load.continue4 -; CHECK: pred.load.if3: -; CHECK-NEXT: [[TMP7:%.*]] = load i32, i32* [[SRC]], align 4 -; CHECK-NEXT: [[TMP8:%.*]] = insertelement <4 x i32> [[TMP5]], i32 [[TMP7]], i32 1 -; CHECK-NEXT: br label %pred.load.continue4 -; CHECK: pred.load.continue4: -; CHECK-NEXT: [[TMP9:%.*]] = phi <4 x i32> [ [[TMP5]], %pred.load.continue ], [ [[TMP8]], %pred.load.if3 ] -; CHECK-NEXT: [[TMP10:%.*]] = extractelement <4 x i1> [[TMP1]], i32 2 -; CHECK-NEXT: br i1 [[TMP10]], label [[PRED_LOAD_IF5:%.*]], label %pred.load.continue6 -; CHECK: pred.load.if5: -; CHECK-NEXT: [[TMP11:%.*]] = load i32, i32* [[SRC]], align 4 -; CHECK-NEXT: [[TMP12:%.*]] = insertelement <4 x i32> [[TMP9]], i32 [[TMP11]], i32 2 -; CHECK-NEXT: br label %pred.load.continue6 -; CHECK: pred.load.continue6: -; CHECK-NEXT: [[TMP13:%.*]] = phi <4 x i32> [ [[TMP9]], %pred.load.continue4 ], [ [[TMP12]], %pred.load.if5 ] -; CHECK-NEXT: [[TMP14:%.*]] = extractelement <4 x i1> [[TMP1]], i32 3 -; CHECK-NEXT: br i1 [[TMP14]], label [[PRED_LOAD_IF7:%.*]], label %pred.load.continue8 -; CHECK: pred.load.if7: -; CHECK-NEXT: [[TMP15:%.*]] = load i32, i32* [[SRC]], align 4 -; CHECK-NEXT: [[TMP16:%.*]] = insertelement <4 x i32> [[TMP13]], i32 [[TMP15]], i32 3 -; CHECK-NEXT: br label %pred.load.continue8 -; CHECK: pred.load.continue8: -; CHECK-NEXT: [[TMP17:%.*]] = phi <4 x i32> [ [[TMP13]], %pred.load.continue6 ], [ [[TMP16]], [[PRED_LOAD_IF7]] ] -; CHECK-NEXT: [[TMP18:%.*]] = getelementptr inbounds i32, i32* [[DST:%.*]], i64 [[TMP0]] -; CHECK-NEXT: [[TMP19:%.*]] = getelementptr inbounds i32, i32* [[TMP18]], i32 0 -; CHECK-NEXT: [[TMP20:%.*]] = bitcast i32* [[TMP19]] to <4 x i32>* -; CHECK-NEXT: call void @llvm.masked.store.v4i32.p0v4i32(<4 x i32> [[TMP17]], <4 x i32>* [[TMP20]], i32 4, <4 x i1> [[TMP1]]) -; CHECK-NEXT: [[INDEX_NEXT]] = add i64 [[INDEX]], 4 -; CHECK-NEXT: [[TMP21:%.*]] = icmp eq i64 [[INDEX_NEXT]], %n.vec -; CHECK-NEXT: br i1 [[TMP21]], label [[MIDDLE_BLOCK:%.*]], label %vector.body +; CHECK-NEXT: [[IDX:%.*]] = phi i64 [ 0, %vector.ph ], [ [[IDX_NEXT:%.*]], %vector.body ] +; CHECK-NEXT: [[TMP1:%.*]] = insertelement <4 x i64> poison, i64 [[IDX]], i32 0 +; CHECK-NEXT: [[TMP2:%.*]] = shufflevector <4 x i64> [[TMP1]], <4 x i64> poison, <4 x i32> zeroinitializer +; CHECK-NEXT: [[INDUCTION:%.*]] = add <4 x i64> [[TMP2]], +; CHECK-NEXT: [[TMP3:%.*]] = add i64 [[IDX]], 0 +; CHECK-NEXT: [[LOOP_PRED:%.*]] = icmp ule <4 x i64> [[INDUCTION]] +; CHECK-NEXT: [[LOAD_VAL:%.*]] = load i32, i32* %src, align 4 +; CHECK-NOT: load i32, i32* %src, align 4 +; CHECK-NEXT: [[TMP4:%.*]] = insertelement <4 x i32> poison, i32 [[LOAD_VAL]], i32 0 +; CHECK-NEXT: [[TMP5:%.*]] = shufflevector <4 x i32> [[TMP4]], <4 x i32> poison, <4 x i32> zeroinitializer +; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, i32* %dst, i64 [[TMP3]] +; CHECK-NEXT: [[TMP7:%.*]] = getelementptr inbounds i32, i32* [[TMP6]], i32 0 +; CHECK-NEXT: [[STORE_PTR:%.*]] = bitcast i32* [[TMP7]] to <4 x i32>* +; CHECK-NEXT: call void @llvm.masked.store.v4i32.p0v4i32(<4 x i32> [[TMP5]], <4 x i32>* [[STORE_PTR]], i32 4, <4 x i1> [[LOOP_PRED]]) +; CHECK-NEXT: [[IDX_NEXT]] = add i64 [[IDX]], 4 +; CHECK-NEXT: [[CMP:%.*]] = icmp eq i64 [[IDX_NEXT]], %n.vec +; CHECK-NEXT: br i1 [[CMP]], label %middle.block, label %vector.body entry: br label %for.body