Index: lib/Transforms/Scalar/LoopDistribute.cpp =================================================================== --- lib/Transforms/Scalar/LoopDistribute.cpp +++ lib/Transforms/Scalar/LoopDistribute.cpp @@ -682,6 +682,8 @@ // Currently, we only distribute to isolate the part of the loop with // dependence cycles to enable partial vectorization. + // TODO: Distribution of volatile may be possible under some circumstance, + // but the current implementation does not touch them. if (LAI->canVectorizeMemory()) return fail("MemOpsCanBeVectorized", "memory operations are safe for vectorization"); Index: test/Transforms/LoopDistribute/basic-with-memchecks.ll =================================================================== --- test/Transforms/LoopDistribute/basic-with-memchecks.ll +++ test/Transforms/LoopDistribute/basic-with-memchecks.ll @@ -23,6 +23,7 @@ @D = common global i32* null, align 8 @E = common global i32* null, align 8 +; CHECK-LABEL: @f( define void @f() { entry: %a = load i32*, i32** @A, align 8 @@ -108,3 +109,63 @@ for.end: ; preds = %for.body ret void } + +; Make sure there's no "Multiple reports generated" assert with a +; volatile load, and no distribution +; CHECK-LABEL: @f_volatile_load( +; CHECK: br label %for.body{{$}} + +; CHECK-NOT: load + +; CHECK: {{^}}for.body: +; CHECK: load i32 +; CHECK: load i32 +; CHECK: load volatile i32 +; CHECK: load i32 +; CHECK: br i1 %exitcond, label %for.end, label %for.body{{$}} + +; CHECK-NOT: load + +; VECTORIZE-NOT: load <4 x i32> +; VECTORIZE-NOT: mul <4 x i32> +define void @f_volatile_load() { +entry: + %a = load i32*, i32** @A, align 8 + %b = load i32*, i32** @B, align 8 + %c = load i32*, i32** @C, align 8 + %d = load i32*, i32** @D, align 8 + %e = load i32*, i32** @E, align 8 + br label %for.body + +for.body: + %ind = phi i64 [ 0, %entry ], [ %add, %for.body ] + + %arrayidxA = getelementptr inbounds i32, i32* %a, i64 %ind + %loadA = load i32, i32* %arrayidxA, align 4 + + %arrayidxB = getelementptr inbounds i32, i32* %b, i64 %ind + %loadB = load i32, i32* %arrayidxB, align 4 + + %mulA = mul i32 %loadB, %loadA + + %add = add nuw nsw i64 %ind, 1 + %arrayidxA_plus_4 = getelementptr inbounds i32, i32* %a, i64 %add + store i32 %mulA, i32* %arrayidxA_plus_4, align 4 + + %arrayidxD = getelementptr inbounds i32, i32* %d, i64 %ind + %loadD = load volatile i32, i32* %arrayidxD, align 4 + + %arrayidxE = getelementptr inbounds i32, i32* %e, i64 %ind + %loadE = load i32, i32* %arrayidxE, align 4 + + %mulC = mul i32 %loadD, %loadE + + %arrayidxC = getelementptr inbounds i32, i32* %c, i64 %ind + store i32 %mulC, i32* %arrayidxC, align 4 + + %exitcond = icmp eq i64 %add, 20 + br i1 %exitcond, label %for.end, label %for.body + +for.end: + ret void +} Index: test/Transforms/LoopVectorize/read-only.ll =================================================================== --- test/Transforms/LoopVectorize/read-only.ll +++ test/Transforms/LoopVectorize/read-only.ll @@ -29,3 +29,33 @@ %sum.0.lcssa = phi i32 [ 0, %0 ], [ %9, %.lr.ph ] ret i32 %sum.0.lcssa } + +; Ensure that volatile loads are not vectorized in a read-only loop. + +;CHECK-LABEL: @read_only_func_volatile( +;CHECK-NOT: load <4 x i32> +;CHECK: ret i32 +define i32 @read_only_func_volatile(i32* nocapture %A, i32* nocapture %B, i32 %n) nounwind uwtable readonly ssp { + %1 = icmp sgt i32 %n, 0 + br i1 %1, label %.lr.ph, label %._crit_edge + +.lr.ph: ; preds = %0, %.lr.ph + %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ] + %sum.02 = phi i32 [ %9, %.lr.ph ], [ 0, %0 ] + %2 = getelementptr inbounds i32, i32* %A, i64 %indvars.iv + %3 = load volatile i32, i32* %2, align 4 + %4 = add nsw i64 %indvars.iv, 13 + %5 = getelementptr inbounds i32, i32* %B, i64 %4 + %6 = load i32, i32* %5, align 4 + %7 = shl i32 %6, 1 + %8 = add i32 %3, %sum.02 + %9 = add i32 %8, %7 + %indvars.iv.next = add i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %._crit_edge, label %.lr.ph + +._crit_edge: ; preds = %.lr.ph, %0 + %sum.0.lcssa = phi i32 [ 0, %0 ], [ %9, %.lr.ph ] + ret i32 %sum.0.lcssa +} Index: test/Transforms/LoopVectorize/write-only.ll =================================================================== --- test/Transforms/LoopVectorize/write-only.ll +++ test/Transforms/LoopVectorize/write-only.ll @@ -23,3 +23,26 @@ ._crit_edge: ; preds = %.lr.ph, %0 ret i32 undef } + +; Ensure that volatile stores are not vectorized. +; CHECK-LABEL: @read_mod_write_single_ptr_volatile_store( +; CHECK-NOT: store <4 x float> +; CHECK: ret i32 +define i32 @read_mod_write_single_ptr_volatile_store(float* nocapture %a, i32 %n) nounwind uwtable ssp { + %1 = icmp sgt i32 %n, 0 + br i1 %1, label %.lr.ph, label %._crit_edge + +.lr.ph: ; preds = %0, %.lr.ph + %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ] + %2 = getelementptr inbounds float, float* %a, i64 %indvars.iv + %3 = load float, float* %2, align 4 + %4 = fmul float %3, 3.000000e+00 + store volatile float %4, float* %2, align 4 + %indvars.iv.next = add i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %._crit_edge, label %.lr.ph + +._crit_edge: ; preds = %.lr.ph, %0 + ret i32 undef +}