Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp =================================================================== --- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -5638,7 +5638,16 @@ continue; Value *Ptr = getPointerOperand(&I); - int64_t Stride = getPtrStride(PSE, Ptr, TheLoop, Strides); + // We don't check wrapping here because we don't know yet if Ptr will be + // part of a full group or a group with gaps. Checking wrapping for all + // pointers (even those that end up in groups with no gaps) will be overly + // conservative. For full groups, wrapping should be ok since if we would + // wrap around the address space we would do a memory access at nullptr + // even without the transformation. The wrapping checks are therefore + // deferred until after we've formed the interleaved groups. + int64_t Stride = + getPtrStride(PSE, Ptr, TheLoop, Strides, + /*Assume=*/false, /*ShouldCheckWrap=*/false); const SCEV *Scev = replaceSymbolicStrideSCEV(PSE, Strides, Ptr); PointerType *PtrTy = dyn_cast(Ptr->getType()); @@ -5842,6 +5851,34 @@ if (Group->getNumMembers() != Group->getFactor()) releaseGroup(Group); + // Remove interleaved groups with gaps (currently only loads) whose memory + // accesses may wrap around. We have to revisit the getPtrStride analysis, + // this time with ShouldCheckWrap=true, since collectConstStrideAccesses does + // not check wrapping (see documentation there). + // FORNOW we use Assume=false; + // TODO: Change to Assume=true but making sure we don't exceed the threshold + // of runtime SCEV assumptions checks (thereby potentially failing to + // vectorize altogether). + for (InterleaveGroup *Group : LoadGroups) { + // Full groups are of no concern, skip them. + if (Group->getNumMembers() == Group->getFactor()) + continue; + + for (unsigned I = 0; I < Group->getFactor(); ++I) { + Instruction *Member = Group->getMember(I); + // Skip the gaps in the group. + if (!Member) + continue; + Value *Ptr = getPointerOperand(Member); + int Stride = getPtrStride(PSE, Ptr, TheLoop, Strides, /*Assume=*/false, + /*ShouldCheckWrap=*/true); + if (Stride == 0) { + releaseGroup(Group); + break; + } + } + } + // If there is a non-reversed interleaved load group with gaps, we will need // to execute at least one scalar epilogue iteration. This will ensure that // we don't speculatively access memory out-of-bounds. Note that we only need Index: llvm/test/Transforms/LoopVectorize/AArch64/gather-cost.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/AArch64/gather-cost.ll +++ llvm/test/Transforms/LoopVectorize/AArch64/gather-cost.ll @@ -1,4 +1,4 @@ -; RUN: opt -loop-vectorize -mtriple=arm64-apple-ios -S -mcpu=cyclone < %s | FileCheck %s +; RUN: opt -loop-vectorize -mtriple=arm64-apple-ios -S -mcpu=cyclone -enable-interleaved-mem-accesses=false < %s | FileCheck %s target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n32:64-S128" @kernel = global [512 x float] zeroinitializer, align 16 Index: llvm/test/Transforms/LoopVectorize/ARM/gather-cost.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/ARM/gather-cost.ll +++ llvm/test/Transforms/LoopVectorize/ARM/gather-cost.ll @@ -1,4 +1,4 @@ -; RUN: opt -loop-vectorize -mtriple=thumbv7s-apple-ios6.0.0 -S < %s | FileCheck %s +; RUN: opt -loop-vectorize -mtriple=thumbv7s-apple-ios6.0.0 -S -enable-interleaved-mem-accesses=false < %s | FileCheck %s target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32" Index: llvm/test/Transforms/LoopVectorize/interleaved-accesses-1.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/interleaved-accesses-1.ll +++ llvm/test/Transforms/LoopVectorize/interleaved-accesses-1.ll @@ -0,0 +1,78 @@ +; RUN: opt -S -loop-vectorize -instcombine -force-vector-width=4 -force-vector-interleave=1 -enable-interleaved-mem-accesses=true < %s | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +; Check that the interleaved-mem-access analysis identifies the access +; to array 'in' as interleaved, despite the possibly wrapping unsigned +; 'out_ix' index. +; +; In this test the interleave-groups are full (have no gaps), so no wrapping +; checks are necessary. We can call getPtrStride with Assume=false and +; ShouldCheckWrap=false to safely figure out that the stride is 2. + +; #include +; class Complex { +; private: +; float real_; +; float imaginary_; +; +;public: +; Complex() : real_(0), imaginary_(0) { } +; Complex(float real, float imaginary) : real_(real), imaginary_(imaginary) { } +; Complex(const Complex &rhs) : real_(rhs.real()), imaginary_(rhs.imaginary()) { } +; +; inline float real() const { return real_; } +; inline float imaginary() const { return imaginary_; } +;}; +; +;void test(Complex * __restrict__ out, Complex * __restrict__ in, size_t out_start, size_t size) +;{ +; for (size_t out_offset = 0; out_offset < size; ++out_offset) +; { +; size_t out_ix = out_start + out_offset; +; Complex t0 = in[out_ix]; +; out[out_ix] = t0; +; } +;} + +; CHECK: vector.body: +; CHECK: %wide.vec = load <8 x i32>, <8 x i32>* {{.*}}, align 4 +; CHECK: shufflevector <8 x i32> %wide.vec, <8 x i32> undef, <4 x i32> +; CHECK: shufflevector <8 x i32> %wide.vec, <8 x i32> undef, <4 x i32> + +%class.Complex = type { float, float } + +define void @_Z4testP7ComplexS0_mm(%class.Complex* noalias nocapture %out, %class.Complex* noalias nocapture readonly %in, i64 %out_start, i64 %size) local_unnamed_addr { +entry: + %cmp9 = icmp eq i64 %size, 0 + br i1 %cmp9, label %for.cond.cleanup, label %for.body.preheader + +for.body.preheader: + br label %for.body + +for.cond.cleanup.loopexit: + br label %for.cond.cleanup + +for.cond.cleanup: + ret void + +for.body: + %out_offset.010 = phi i64 [ %inc, %for.body ], [ 0, %for.body.preheader ] + %add = add i64 %out_offset.010, %out_start + %arrayidx = getelementptr inbounds %class.Complex, %class.Complex* %in, i64 %add + %0 = bitcast %class.Complex* %arrayidx to i32* + %1 = load i32, i32* %0, align 4 + %imaginary_.i.i = getelementptr inbounds %class.Complex, %class.Complex* %in, i64 %add, i32 1 + %2 = bitcast float* %imaginary_.i.i to i32* + %3 = load i32, i32* %2, align 4 + %arrayidx1 = getelementptr inbounds %class.Complex, %class.Complex* %out, i64 %add + %4 = bitcast %class.Complex* %arrayidx1 to i64* + %t0.sroa.4.0.insert.ext = zext i32 %3 to i64 + %t0.sroa.4.0.insert.shift = shl nuw i64 %t0.sroa.4.0.insert.ext, 32 + %t0.sroa.0.0.insert.ext = zext i32 %1 to i64 + %t0.sroa.0.0.insert.insert = or i64 %t0.sroa.4.0.insert.shift, %t0.sroa.0.0.insert.ext + store i64 %t0.sroa.0.0.insert.insert, i64* %4, align 4 + %inc = add nuw i64 %out_offset.010, 1 + %exitcond = icmp eq i64 %inc, %size + br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body +} Index: llvm/test/Transforms/LoopVectorize/interleaved-accesses-2.ll =================================================================== --- llvm/test/Transforms/LoopVectorize/interleaved-accesses-2.ll +++ llvm/test/Transforms/LoopVectorize/interleaved-accesses-2.ll @@ -0,0 +1,58 @@ +; RUN: opt -S -loop-vectorize -instcombine -force-vector-width=4 -force-vector-interleave=1 -enable-interleaved-mem-accesses=true < %s | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +; Check that the interleaved-mem-access analysis identifies the access +; to array 'in' as interleaved, despite the possibly wrapping unsigned +; 'out_ix' index. +; +; In this test the interleave-group of the loads is not full (has gaps), so +; the wrapping checks are necessary. Here this cannot be done statically so +; runtime checks are needed, but with Assume=false getPtrStride cannot add +; runtime checks and as a result we can't create the interleave-group (because +; we can't be sure that the stride is 2). +; FIXME: This is currently a missed optimization until we can use Assume=true +; with proper threshold checks. +; XFAIL: * + +; #include +; void test(float * __restrict__ out, float * __restrict__ in, size_t size) +; { +; for (size_t out_offset = 0; out_offset < size; ++out_offset) +; { +; float t0 = in[2*out_offset]; +; out[out_offset] = t0; +; } +; } + +; CHECK: vector.body: +; CHECK: %wide.vec = load <8 x i32>, <8 x i32>* {{.*}}, align 4 +; CHECK: shufflevector <8 x i32> %wide.vec, <8 x i32> undef, <4 x i32> + +define void @_Z4testPfS_m(float* noalias nocapture %out, float* noalias nocapture readonly %in, i64 %size) local_unnamed_addr { +entry: + %cmp7 = icmp eq i64 %size, 0 + br i1 %cmp7, label %for.cond.cleanup, label %for.body.preheader + +for.body.preheader: + br label %for.body + +for.cond.cleanup.loopexit: + br label %for.cond.cleanup + +for.cond.cleanup: + ret void + +for.body: + %out_offset.08 = phi i64 [ %inc, %for.body ], [ 0, %for.body.preheader ] + %mul = shl i64 %out_offset.08, 1 + %arrayidx = getelementptr inbounds float, float* %in, i64 %mul + %0 = bitcast float* %arrayidx to i32* + %1 = load i32, i32* %0, align 4 + %arrayidx1 = getelementptr inbounds float, float* %out, i64 %out_offset.08 + %2 = bitcast float* %arrayidx1 to i32* + store i32 %1, i32* %2, align 4 + %inc = add nuw i64 %out_offset.08, 1 + %exitcond = icmp eq i64 %inc, %size + br i1 %exitcond, label %for.cond.cleanup.loopexit, label %for.body +}