[PATCH] llvm.noalias - don't prevent loop vectorization

[Arnold Schwaighofer]

LGTM.

On 04/30/15 08:27 AM, "hfinkel at anl.gov"  wrote:
> 
> Hi chandlerc, reames, aschwaighofer,
> 
> This is part of the series started by D9375, and teaches the loop vectorizer enough about llvm.noalias that it should not interfere with vectorization when it happens to appear inside a loop we might otherwise vectorize.
> 
> http://reviews.llvm.org/D9382
> 
> Files:
> include/llvm/Analysis/TargetTransformInfoImpl.h
> include/llvm/Transforms/Utils/VectorUtils.h
> lib/Transforms/Vectorize/LoopVectorize.cpp
> test/Transforms/LoopVectorize/noalias.ll
> 
> Index: include/llvm/Analysis/TargetTransformInfoImpl.h
> ===================================================================
> --- include/llvm/Analysis/TargetTransformInfoImpl.h
> +++ include/llvm/Analysis/TargetTransformInfoImpl.h
> @@ -149,6 +149,7 @@
> case Intrinsic::invariant_end:
> case Intrinsic::lifetime_start:
> case Intrinsic::lifetime_end:
> + case Intrinsic::noalias:
> case Intrinsic::objectsize:
> case Intrinsic::ptr_annotation:
> case Intrinsic::var_annotation:
> Index: include/llvm/Transforms/Utils/VectorUtils.h
> ===================================================================
> --- include/llvm/Transforms/Utils/VectorUtils.h
> +++ include/llvm/Transforms/Utils/VectorUtils.h
> @@ -101,7 +101,8 @@
> if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
> Intrinsic::ID ID = II->getIntrinsicID();
> if (isTriviallyVectorizable(ID) || ID == Intrinsic::lifetime_start ||
> - ID == Intrinsic::lifetime_end || ID == Intrinsic::assume)
> + ID == Intrinsic::lifetime_end || ID == Intrinsic::assume ||
> + ID == Intrinsic::noalias)
> return ID;
> else
> return Intrinsic::not_intrinsic;
> Index: lib/Transforms/Vectorize/LoopVectorize.cpp
> ===================================================================
> --- lib/Transforms/Vectorize/LoopVectorize.cpp
> +++ lib/Transforms/Vectorize/LoopVectorize.cpp
> @@ -3144,20 +3144,21 @@
> Module *M = BB->getParent()->getParent();
> CallInst *CI = cast<CallInst>(it);
> 
> + Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI);
> + if (ID &&
> + (ID == Intrinsic::assume || ID == Intrinsic::lifetime_end ||
> + ID == Intrinsic::lifetime_start || ID == Intrinsic::noalias)) {
> + scalarizeInstruction(it);
> + break;
> + }
> +
> StringRef FnName = CI->getCalledFunction()->getName();
> Function *F = CI->getCalledFunction();
> Type *RetTy = ToVectorTy(CI->getType(), VF);
> SmallVector<Type *, 4> Tys;
> for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i)
> Tys.push_back(ToVectorTy(CI->getArgOperand(i)->getType(), VF));
> 
> - Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI);
> - if (ID &&
> - (ID == Intrinsic::assume || ID == Intrinsic::lifetime_end ||
> - ID == Intrinsic::lifetime_start)) {
> - scalarizeInstruction(it);
> - break;
> - }
> // The flag shows whether we use Intrinsic or a usual Call for vectorized
> // version of the instruction.
> // Is it beneficial to perform intrinsic call compared to lib call?
> Index: test/Transforms/LoopVectorize/noalias.ll
> ===================================================================
> --- /dev/null
> +++ test/Transforms/LoopVectorize/noalias.ll
> @@ -0,0 +1,34 @@
> +; RUN: opt -S -loop-vectorize -force-vector-width=2 -force-vector-interleave=1 < %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-s0:64:64-f80:128:128-n8:16:32:64-S128"
> +
> +; Make sure we can vectorize loops which contain lifetime markers.
> +
> +; CHECK-LABEL: @test(
> +; CHECK: @llvm.noalias.p0i32
> +; CHECK: store <2 x i32>
> +
> +define void @test(i32 *%d) {
> +entry:
> + br label %for.body
> +
> +for.body:
> + %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
> + %d2 = call i32* @llvm.noalias.p0i32(i32* %d, metadata !1)
> + %arrayidx = getelementptr inbounds i32, i32* %d2, i64 %indvars.iv
> + %v1 = load i32, i32* %arrayidx, align 8
> + store i32 100, i32* %arrayidx, align 8
> + %indvars.iv.next = add i64 %indvars.iv, 1
> + %lftr.wideiv = trunc i64 %indvars.iv.next to i32
> + %exitcond = icmp ne i32 %lftr.wideiv, 128
> + br i1 %exitcond, label %for.body, label %for.end
> +
> +for.end:
> + ret void
> +}
> +
> +declare i32* @llvm.noalias.p0i32(i32*, metadata) nounwind
> +
> +!0 = !{!0, !"some domain"}
> +!1 = !{!1, !0, !"some scope"}
> +
> 
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