summaryrefslogtreecommitdiffstats
path: root/llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll')
-rw-r--r--llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll292
1 files changed, 292 insertions, 0 deletions
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll b/llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll
new file mode 100644
index 00000000000..34d06ef12ea
--- /dev/null
+++ b/llvm/test/Analysis/LoopAccessAnalysis/wrapping-pointer-versioning.ll
@@ -0,0 +1,292 @@
+; RUN: opt -basicaa -loop-accesses -analyze < %s | FileCheck %s -check-prefix=LAA
+; RUN: opt -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -S < %s | FileCheck %s -check-prefix=LV
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+; For this loop:
+; unsigned index = 0;
+; for (int i = 0; i < n; i++) {
+; A[2 * index] = A[2 * index] + B[i];
+; index++;
+; }
+;
+; SCEV is unable to prove that A[2 * i] does not overflow.
+;
+; Analyzing the IR does not help us because the GEPs are not
+; affine AddRecExprs. However, we can turn them into AddRecExprs
+; using SCEV Predicates.
+;
+; Once we have an affine expression we need to add an additional NUSW
+; to check that the pointers don't wrap since the GEPs are not
+; inbound.
+
+; LAA-LABEL: f1
+; LAA: Memory dependences are safe{{$}}
+; LAA: SCEV assumptions:
+; LAA-NEXT: {0,+,2}<%for.body> Added Flags: <nusw>
+; LAA-NEXT: {%a,+,4}<%for.body> Added Flags: <nusw>
+
+; The expression for %mul_ext as analyzed by SCEV is
+; (zext i32 {0,+,2}<%for.body> to i64)
+; We have added the nusw flag to turn this expression into the SCEV expression:
+; i64 {0,+,2}<%for.body>
+
+; LV-LABEL: f1
+; LV-LABEL: vector.scevcheck
+; LV: [[PredCheck0:%[^ ]*]] = icmp ne i128
+; LV: [[Or0:%[^ ]*]] = or i1 false, [[PredCheck0]]
+; LV: [[PredCheck1:%[^ ]*]] = icmp ne i128
+; LV: [[FinalCheck:%[^ ]*]] = or i1 [[Or0]], [[PredCheck1]]
+; LV: br i1 [[FinalCheck]], label %scalar.ph, label %vector.ph
+define void @f1(i16* noalias %a,
+ i16* noalias %b, i64 %N) {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+ %ind1 = phi i32 [ 0, %entry ], [ %inc1, %for.body ]
+
+ %mul = mul i32 %ind1, 2
+ %mul_ext = zext i32 %mul to i64
+
+ %arrayidxA = getelementptr i16, i16* %a, i64 %mul_ext
+ %loadA = load i16, i16* %arrayidxA, align 2
+
+ %arrayidxB = getelementptr i16, i16* %b, i64 %ind
+ %loadB = load i16, i16* %arrayidxB, align 2
+
+ %add = mul i16 %loadA, %loadB
+
+ store i16 %add, i16* %arrayidxA, align 2
+
+ %inc = add nuw nsw i64 %ind, 1
+ %inc1 = add i32 %ind1, 1
+
+ %exitcond = icmp eq i64 %inc, %N
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret void
+}
+
+; For this loop:
+; unsigned index = n;
+; for (int i = 0; i < n; i++) {
+; A[2 * index] = A[2 * index] + B[i];
+; index--;
+; }
+;
+; the SCEV expression for 2 * index is not an AddRecExpr
+; (and implictly not affine). However, we are able to make assumptions
+; that will turn the expression into an affine one and continue the
+; analysis.
+;
+; Once we have an affine expression we need to add an additional NUSW
+; to check that the pointers don't wrap since the GEPs are not
+; inbounds.
+;
+; This loop has a negative stride for A, and the nusw flag is required in
+; order to properly extend the increment from i32 -4 to i64 -4.
+
+; LAA-LABEL: f2
+; LAA: Memory dependences are safe{{$}}
+; LAA: SCEV assumptions:
+; LAA-NEXT: {(2 * (trunc i64 %N to i32)),+,-2}<%for.body> Added Flags: <nusw>
+; LAA-NEXT: {((2 * (zext i32 (2 * (trunc i64 %N to i32)) to i64)) + %a),+,-4}<%for.body> Added Flags: <nusw>
+
+; The expression for %mul_ext as analyzed by SCEV is
+; (zext i32 {(2 * (trunc i64 %N to i32)),+,-2}<%for.body> to i64)
+; We have added the nusw flag to turn this expression into the following SCEV:
+; i64 {zext i32 (2 * (trunc i64 %N to i32)) to i64,+,-2}<%for.body>
+
+; LV-LABEL: f2
+; LV-LABEL: vector.scevcheck
+; LV: [[PredCheck0:%[^ ]*]] = icmp ne i128
+; LV: [[Or0:%[^ ]*]] = or i1 false, [[PredCheck0]]
+; LV: [[PredCheck1:%[^ ]*]] = icmp ne i128
+; LV: [[FinalCheck:%[^ ]*]] = or i1 [[Or0]], [[PredCheck1]]
+; LV: br i1 [[FinalCheck]], label %scalar.ph, label %vector.ph
+define void @f2(i16* noalias %a,
+ i16* noalias %b, i64 %N) {
+entry:
+ %TruncN = trunc i64 %N to i32
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+ %ind1 = phi i32 [ %TruncN, %entry ], [ %dec, %for.body ]
+
+ %mul = mul i32 %ind1, 2
+ %mul_ext = zext i32 %mul to i64
+
+ %arrayidxA = getelementptr i16, i16* %a, i64 %mul_ext
+ %loadA = load i16, i16* %arrayidxA, align 2
+
+ %arrayidxB = getelementptr i16, i16* %b, i64 %ind
+ %loadB = load i16, i16* %arrayidxB, align 2
+
+ %add = mul i16 %loadA, %loadB
+
+ store i16 %add, i16* %arrayidxA, align 2
+
+ %inc = add nuw nsw i64 %ind, 1
+ %dec = sub i32 %ind1, 1
+
+ %exitcond = icmp eq i64 %inc, %N
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret void
+}
+
+; We replicate the tests above, but this time sign extend 2 * index instead
+; of zero extending it.
+
+; LAA-LABEL: f3
+; LAA: Memory dependences are safe{{$}}
+; LAA: SCEV assumptions:
+; LAA-NEXT: {0,+,2}<%for.body> Added Flags: <nssw>
+; LAA-NEXT: {%a,+,4}<%for.body> Added Flags: <nusw>
+
+; The expression for %mul_ext as analyzed by SCEV is
+; i64 (sext i32 {0,+,2}<%for.body> to i64)
+; We have added the nssw flag to turn this expression into the following SCEV:
+; i64 {0,+,2}<%for.body>
+
+; LV-LABEL: f3
+; LV-LABEL: vector.scevcheck
+; LV: [[PredCheck0:%[^ ]*]] = icmp ne i128
+; LV: [[Or0:%[^ ]*]] = or i1 false, [[PredCheck0]]
+; LV: [[PredCheck1:%[^ ]*]] = icmp ne i128
+; LV: [[FinalCheck:%[^ ]*]] = or i1 [[Or0]], [[PredCheck1]]
+; LV: br i1 [[FinalCheck]], label %scalar.ph, label %vector.ph
+define void @f3(i16* noalias %a,
+ i16* noalias %b, i64 %N) {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+ %ind1 = phi i32 [ 0, %entry ], [ %inc1, %for.body ]
+
+ %mul = mul i32 %ind1, 2
+ %mul_ext = sext i32 %mul to i64
+
+ %arrayidxA = getelementptr i16, i16* %a, i64 %mul_ext
+ %loadA = load i16, i16* %arrayidxA, align 2
+
+ %arrayidxB = getelementptr i16, i16* %b, i64 %ind
+ %loadB = load i16, i16* %arrayidxB, align 2
+
+ %add = mul i16 %loadA, %loadB
+
+ store i16 %add, i16* %arrayidxA, align 2
+
+ %inc = add nuw nsw i64 %ind, 1
+ %inc1 = add i32 %ind1, 1
+
+ %exitcond = icmp eq i64 %inc, %N
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret void
+}
+
+; LAA-LABEL: f4
+; LAA: Memory dependences are safe{{$}}
+; LAA: SCEV assumptions:
+; LAA-NEXT: {(2 * (trunc i64 %N to i32)),+,-2}<%for.body> Added Flags: <nssw>
+; LAA-NEXT: {((2 * (sext i32 (2 * (trunc i64 %N to i32)) to i64)) + %a),+,-4}<%for.body> Added Flags: <nusw>
+
+; The expression for %mul_ext as analyzed by SCEV is
+; i64 (sext i32 {(2 * (trunc i64 %N to i32)),+,-2}<%for.body> to i64)
+; We have added the nssw flag to turn this expression into the following SCEV:
+; i64 {sext i32 (2 * (trunc i64 %N to i32)) to i64,+,-2}<%for.body>
+
+; LV-LABEL: f4
+; LV-LABEL: vector.scevcheck
+; LV: [[PredCheck0:%[^ ]*]] = icmp ne i128
+; LV: [[Or0:%[^ ]*]] = or i1 false, [[PredCheck0]]
+; LV: [[PredCheck1:%[^ ]*]] = icmp ne i128
+; LV: [[FinalCheck:%[^ ]*]] = or i1 [[Or0]], [[PredCheck1]]
+; LV: br i1 [[FinalCheck]], label %scalar.ph, label %vector.ph
+define void @f4(i16* noalias %a,
+ i16* noalias %b, i64 %N) {
+entry:
+ %TruncN = trunc i64 %N to i32
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+ %ind1 = phi i32 [ %TruncN, %entry ], [ %dec, %for.body ]
+
+ %mul = mul i32 %ind1, 2
+ %mul_ext = sext i32 %mul to i64
+
+ %arrayidxA = getelementptr i16, i16* %a, i64 %mul_ext
+ %loadA = load i16, i16* %arrayidxA, align 2
+
+ %arrayidxB = getelementptr i16, i16* %b, i64 %ind
+ %loadB = load i16, i16* %arrayidxB, align 2
+
+ %add = mul i16 %loadA, %loadB
+
+ store i16 %add, i16* %arrayidxA, align 2
+
+ %inc = add nuw nsw i64 %ind, 1
+ %dec = sub i32 %ind1, 1
+
+ %exitcond = icmp eq i64 %inc, %N
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret void
+}
+
+; The following function is similar to the one above, but has the GEP
+; to pointer %A inbounds. The index %mul doesn't have the nsw flag.
+; This means that the SCEV expression for %mul can wrap and we need
+; a SCEV predicate to continue analysis.
+;
+; We can still analyze this by adding the required no wrap SCEV predicates.
+
+; LAA-LABEL: f5
+; LAA: Memory dependences are safe{{$}}
+; LAA: SCEV assumptions:
+; LAA-NEXT: {(2 * (trunc i64 %N to i32)),+,-2}<%for.body> Added Flags: <nssw>
+; LAA-NEXT: {((2 * (sext i32 (2 * (trunc i64 %N to i32)) to i64)) + %a),+,-4}<%for.body> Added Flags: <nusw>
+
+; LV-LABEL: f5
+; LV-LABEL: vector.scevcheck
+define void @f5(i16* noalias %a,
+ i16* noalias %b, i64 %N) {
+entry:
+ %TruncN = trunc i64 %N to i32
+ br label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %ind = phi i64 [ 0, %entry ], [ %inc, %for.body ]
+ %ind1 = phi i32 [ %TruncN, %entry ], [ %dec, %for.body ]
+
+ %mul = mul i32 %ind1, 2
+
+ %arrayidxA = getelementptr inbounds i16, i16* %a, i32 %mul
+ %loadA = load i16, i16* %arrayidxA, align 2
+
+ %arrayidxB = getelementptr inbounds i16, i16* %b, i64 %ind
+ %loadB = load i16, i16* %arrayidxB, align 2
+
+ %add = mul i16 %loadA, %loadB
+
+ store i16 %add, i16* %arrayidxA, align 2
+
+ %inc = add nuw nsw i64 %ind, 1
+ %dec = sub i32 %ind1, 1
+
+ %exitcond = icmp eq i64 %inc, %N
+ br i1 %exitcond, label %for.end, label %for.body
+
+for.end: ; preds = %for.body
+ ret void
+}
OpenPOWER on IntegriCloud