[InstSimplify] Consider vscale_range for get active lane mask #160073
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Scalable get_active_lane_mask intrinsic calls can be simplified to i1 splat (ptrue) when its constant range is larger than or equal to the maximum possible number of elements, which can be inferred from vscale_range(x, y)
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llvm:instcombine
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@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-llvm-analysis Author: Matthew Devereau (MDevereau) ChangesScalable get_active_lane_mask intrinsic calls can be simplified to i1 splat (ptrue) when its constant range is larger than or equal to the maximum possible number of elements, which can be inferred from vscale_range(x, y) Patch is 28.34 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/160073.diff 4 Files Affected:
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 7bff13d59528c..cf50b6ea91fb1 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -6474,10 +6474,27 @@ Value *llvm::simplifyBinaryIntrinsic(Intrinsic::ID IID, Type *ReturnType,
const CallBase *Call) {
unsigned BitWidth = ReturnType->getScalarSizeInBits();
switch (IID) {
- case Intrinsic::get_active_lane_mask:
+ case Intrinsic::get_active_lane_mask: {
if (match(Op1, m_Zero()))
return ConstantInt::getFalse(ReturnType);
+
+ const Function *F = Call->getFunction();
+ auto ScalableTy = dyn_cast<ScalableVectorType>(ReturnType);
+ if (ScalableTy && F->hasFnAttribute(Attribute::VScaleRange)) {
+ Attribute Attr = F->getFnAttribute(Attribute::VScaleRange);
+ std::optional<unsigned> VScaleMax = Attr.getVScaleRangeMax();
+ if (!VScaleMax)
+ break;
+ unsigned MaxPossibleMaskElements =
+ ScalableTy->getMinNumElements() * (*VScaleMax);
+
+ const APInt *Op1Val;
+ if (match(Op0, m_Zero()) && match(Op1, m_APInt(Op1Val)) &&
+ Op1Val->uge(MaxPossibleMaskElements))
+ return ConstantInt::getAllOnesValue(ReturnType);
+ }
break;
+ }
case Intrinsic::abs:
// abs(abs(x)) -> abs(x). We don't need to worry about the nsw arg here.
// It is always ok to pick the earlier abs. We'll just lose nsw if its only
diff --git a/llvm/test/Transforms/InstSimplify/get_active_lane_mask.ll b/llvm/test/Transforms/InstSimplify/get_active_lane_mask.ll
index a3b8e4efbe939..180012a4e8211 100644
--- a/llvm/test/Transforms/InstSimplify/get_active_lane_mask.ll
+++ b/llvm/test/Transforms/InstSimplify/get_active_lane_mask.ll
@@ -18,3 +18,51 @@ define <vscale x 8 x i1> @foo_nxv8i1(i32 %a) {
%mask = call <vscale x 8 x i1> @llvm.get.active.lane.mask.nxv8i1(i32 %a, i32 0)
ret <vscale x 8 x i1> %mask
}
+
+define <vscale x 16 x i1> @foo_vscale_max_255() vscale_range(1,16) {
+; CHECK-LABEL: define <vscale x 16 x i1> @foo_vscale_max_255(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: [[MASK:%.*]] = call <vscale x 16 x i1> @llvm.get.active.lane.mask.nxv16i1.i32(i32 0, i32 255)
+; CHECK-NEXT: ret <vscale x 16 x i1> [[MASK]]
+;
+ %mask = call <vscale x 16 x i1> @llvm.get.active.lane.mask.nxv16i1(i32 0, i32 255)
+ ret <vscale x 16 x i1> %mask
+}
+
+define <vscale x 16 x i1> @foo_vscale_max_256() vscale_range(1,16) {
+; CHECK-LABEL: define <vscale x 16 x i1> @foo_vscale_max_256(
+; CHECK-SAME: ) #[[ATTR0]] {
+; CHECK-NEXT: ret <vscale x 16 x i1> splat (i1 true)
+;
+ %mask = call <vscale x 16 x i1> @llvm.get.active.lane.mask.nxv16i1(i32 0, i32 256)
+ ret <vscale x 16 x i1> %mask
+}
+
+define <vscale x 2 x i1> @foo_vscale_max_nxv2i1_1_1_2() vscale_range(1,1) {
+; CHECK-LABEL: define <vscale x 2 x i1> @foo_vscale_max_nxv2i1_1_1_2(
+; CHECK-SAME: ) #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT: ret <vscale x 2 x i1> splat (i1 true)
+;
+ %mask = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1(i32 0, i32 2)
+ ret <vscale x 2 x i1> %mask
+}
+
+define <vscale x 4 x i1> @foo_vscale_max_nxv4i1_2_4_16() vscale_range(2,4) {
+; CHECK-LABEL: define <vscale x 4 x i1> @foo_vscale_max_nxv4i1_2_4_16(
+; CHECK-SAME: ) #[[ATTR2:[0-9]+]] {
+; CHECK-NEXT: ret <vscale x 4 x i1> splat (i1 true)
+;
+ %mask = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1(i128 0, i128 16)
+ ret <vscale x 4 x i1> %mask
+}
+
+define <vscale x 4 x i1> @foo_vscale_max_nxv4i1_2_4_1_16() vscale_range(2,4) {
+; CHECK-LABEL: define <vscale x 4 x i1> @foo_vscale_max_nxv4i1_2_4_1_16(
+; CHECK-SAME: ) #[[ATTR2]] {
+; CHECK-NEXT: [[MASK:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i128(i128 1, i128 16)
+; CHECK-NEXT: ret <vscale x 4 x i1> [[MASK]]
+;
+ %mask = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1(i128 1, i128 16)
+ ret <vscale x 4 x i1> %mask
+}
+
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/masked-call.ll b/llvm/test/Transforms/LoopVectorize/AArch64/masked-call.ll
index c7218ef249a9d..d2ef01028a2d6 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/masked-call.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/masked-call.ll
@@ -52,11 +52,10 @@ define void @test_widen(ptr noalias %a, ptr readnone %b) #4 {
; TFCOMMON-NEXT: [[ENTRY:.*]]:
; TFCOMMON-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFCOMMON-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFCOMMON-NEXT: br label %[[VECTOR_BODY:.*]]
; TFCOMMON: [[VECTOR_BODY]]:
; TFCOMMON-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFCOMMON-NEXT: [[TMP5:%.*]] = getelementptr i64, ptr [[B]], i64 [[INDEX]]
; TFCOMMON-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.masked.load.nxv2i64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> poison)
; TFCOMMON-NEXT: [[TMP6:%.*]] = call <vscale x 2 x i64> @foo_vector(<vscale x 2 x i64> [[WIDE_MASKED_LOAD]], <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
@@ -77,12 +76,11 @@ define void @test_widen(ptr noalias %a, ptr readnone %b) #4 {
; TFA_INTERLEAVE-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; TFA_INTERLEAVE-NEXT: [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
; TFA_INTERLEAVE-NEXT: [[TMP6:%.*]] = shl nuw i64 [[TMP5]], 1
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY1:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[TMP6]], i64 1025)
; TFA_INTERLEAVE-NEXT: br label %[[VECTOR_BODY:.*]]
; TFA_INTERLEAVE: [[VECTOR_BODY]]:
; TFA_INTERLEAVE-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK2:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY1]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT4:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[TMP7:%.*]] = getelementptr i64, ptr [[B]], i64 [[INDEX]]
; TFA_INTERLEAVE-NEXT: [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
@@ -181,11 +179,10 @@ define void @test_if_then(ptr noalias %a, ptr readnone %b) #4 {
; TFCOMMON-NEXT: [[ENTRY:.*]]:
; TFCOMMON-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFCOMMON-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFCOMMON-NEXT: br label %[[VECTOR_BODY:.*]]
; TFCOMMON: [[VECTOR_BODY]]:
; TFCOMMON-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFCOMMON-NEXT: [[TMP5:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
; TFCOMMON-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.masked.load.nxv2i64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> poison)
; TFCOMMON-NEXT: [[TMP6:%.*]] = icmp ugt <vscale x 2 x i64> [[WIDE_MASKED_LOAD]], splat (i64 50)
@@ -209,12 +206,11 @@ define void @test_if_then(ptr noalias %a, ptr readnone %b) #4 {
; TFA_INTERLEAVE-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; TFA_INTERLEAVE-NEXT: [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
; TFA_INTERLEAVE-NEXT: [[TMP6:%.*]] = shl nuw i64 [[TMP5]], 1
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY1:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[TMP6]], i64 1025)
; TFA_INTERLEAVE-NEXT: br label %[[VECTOR_BODY:.*]]
; TFA_INTERLEAVE: [[VECTOR_BODY]]:
; TFA_INTERLEAVE-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK2:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY1]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT5:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
; TFA_INTERLEAVE-NEXT: [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
@@ -335,11 +331,10 @@ define void @test_widen_if_then_else(ptr noalias %a, ptr readnone %b) #4 {
; TFCOMMON-NEXT: [[ENTRY:.*]]:
; TFCOMMON-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFCOMMON-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFCOMMON-NEXT: br label %[[VECTOR_BODY:.*]]
; TFCOMMON: [[VECTOR_BODY]]:
; TFCOMMON-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFCOMMON-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFCOMMON-NEXT: [[TMP5:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
; TFCOMMON-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.masked.load.nxv2i64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> poison)
; TFCOMMON-NEXT: [[TMP6:%.*]] = icmp ugt <vscale x 2 x i64> [[WIDE_MASKED_LOAD]], splat (i64 50)
@@ -366,12 +361,11 @@ define void @test_widen_if_then_else(ptr noalias %a, ptr readnone %b) #4 {
; TFA_INTERLEAVE-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; TFA_INTERLEAVE-NEXT: [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
; TFA_INTERLEAVE-NEXT: [[TMP6:%.*]] = shl nuw i64 [[TMP5]], 1
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY1:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[TMP6]], i64 1025)
; TFA_INTERLEAVE-NEXT: br label %[[VECTOR_BODY:.*]]
; TFA_INTERLEAVE: [[VECTOR_BODY]]:
; TFA_INTERLEAVE-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK2:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY1]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT5:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX]]
; TFA_INTERLEAVE-NEXT: [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
@@ -613,11 +607,10 @@ define void @test_widen_optmask(ptr noalias %a, ptr readnone %b) #4 {
; TFALWAYS-NEXT: [[ENTRY:.*]]:
; TFALWAYS-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFALWAYS-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFALWAYS-NEXT: br label %[[VECTOR_BODY:.*]]
; TFALWAYS: [[VECTOR_BODY]]:
; TFALWAYS-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFALWAYS-NEXT: [[TMP5:%.*]] = getelementptr i64, ptr [[B]], i64 [[INDEX]]
; TFALWAYS-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.masked.load.nxv2i64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> poison)
; TFALWAYS-NEXT: [[TMP6:%.*]] = call <vscale x 2 x i64> @foo_vector(<vscale x 2 x i64> [[WIDE_MASKED_LOAD]], <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
@@ -636,11 +629,10 @@ define void @test_widen_optmask(ptr noalias %a, ptr readnone %b) #4 {
; TFFALLBACK-NEXT: [[ENTRY:.*]]:
; TFFALLBACK-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFFALLBACK-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFFALLBACK-NEXT: br label %[[VECTOR_BODY:.*]]
; TFFALLBACK: [[VECTOR_BODY]]:
; TFFALLBACK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFFALLBACK-NEXT: [[TMP5:%.*]] = getelementptr i64, ptr [[B]], i64 [[INDEX]]
; TFFALLBACK-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.masked.load.nxv2i64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x i64> poison)
; TFFALLBACK-NEXT: [[TMP6:%.*]] = call <vscale x 2 x i64> @foo_vector(<vscale x 2 x i64> [[WIDE_MASKED_LOAD]], <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
@@ -661,12 +653,11 @@ define void @test_widen_optmask(ptr noalias %a, ptr readnone %b) #4 {
; TFA_INTERLEAVE-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; TFA_INTERLEAVE-NEXT: [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
; TFA_INTERLEAVE-NEXT: [[TMP6:%.*]] = shl nuw i64 [[TMP5]], 1
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY1:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[TMP6]], i64 1025)
; TFA_INTERLEAVE-NEXT: br label %[[VECTOR_BODY:.*]]
; TFA_INTERLEAVE: [[VECTOR_BODY]]:
; TFA_INTERLEAVE-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK2:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY1]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT4:%.*]], %[[VECTOR_BODY]] ]
; TFA_INTERLEAVE-NEXT: [[TMP7:%.*]] = getelementptr i64, ptr [[B]], i64 [[INDEX]]
; TFA_INTERLEAVE-NEXT: [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
@@ -770,13 +761,12 @@ define double @test_widen_fmuladd_and_call(ptr noalias %a, ptr readnone %b, doub
; TFALWAYS-NEXT: [[ENTRY:.*]]:
; TFALWAYS-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFALWAYS-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFALWAYS-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x double> poison, double [[M]], i64 0
; TFALWAYS-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x double> [[BROADCAST_SPLATINSERT]], <vscale x 2 x double> poison, <vscale x 2 x i32> zeroinitializer
; TFALWAYS-NEXT: br label %[[VECTOR_BODY:.*]]
; TFALWAYS: [[VECTOR_BODY]]:
; TFALWAYS-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFALWAYS-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFALWAYS-NEXT: [[VEC_PHI:%.*]] = phi double [ 0.000000e+00, %[[ENTRY]] ], [ [[TMP11:%.*]], %[[VECTOR_BODY]] ]
; TFALWAYS-NEXT: [[TMP5:%.*]] = getelementptr double, ptr [[B]], i64 [[INDEX]]
; TFALWAYS-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x double> @llvm.masked.load.nxv2f64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x double> poison)
@@ -800,13 +790,12 @@ define double @test_widen_fmuladd_and_call(ptr noalias %a, ptr readnone %b, doub
; TFFALLBACK-NEXT: [[ENTRY:.*]]:
; TFFALLBACK-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
; TFFALLBACK-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 2
-; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFFALLBACK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x double> poison, double [[M]], i64 0
; TFFALLBACK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x double> [[BROADCAST_SPLATINSERT]], <vscale x 2 x double> poison, <vscale x 2 x i32> zeroinitializer
; TFFALLBACK-NEXT: br label %[[VECTOR_BODY:.*]]
; TFFALLBACK: [[VECTOR_BODY]]:
; TFFALLBACK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
-; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; TFFALLBACK-NEXT: [[ACTIVE_LANE_MASK:%.*]] = phi <vscale x 2 x i1> [ splat (i1 true), %[[ENTRY]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[VECTOR_BODY]] ]
; TFFALLBACK-NEXT: [[VEC_PHI:%.*]] = phi double [ 0.000000e+00, %[[ENTRY]] ], [ [[TMP11:%.*]], %[[VECTOR_BODY]] ]
; TFFALLBACK-NEXT: [[TMP5:%.*]] = getelementptr double, ptr [[B]], i64 [[INDEX]]
; TFFALLBACK-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 2 x double> @llvm.masked.load.nxv2f64.p0(ptr [[TMP5]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]], <vscale x 2 x double> poison)
@@ -832,14 +821,13 @@ define double @test_widen_fmuladd_and_call(ptr noalias %a, ptr readnone %b, doub
; TFA_INTERLEAVE-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; TFA_INTERLEAVE-NEXT: [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
; TFA_INTERLEAVE-NEXT: [[TMP6:%.*]] = shl nuw i64 [[TMP5]], 1
-; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 0, i64 1025)
; TFA_INTERLEAVE-NEXT: [[ACTIVE_LANE_MASK_ENTRY1:%.*]] = call <vscale x 2 x i1> @llvm.get.active.lane.mask.nxv2i1.i64(i64 [[TMP6]], i64 1025)
; TFA_INTERLEAVE-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vsc...
[truncated]
|
MDevereau
changed the title
nikic
reviewed
Sep 22, 2025
Comment on lines
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| if (ScalableTy && F->hasFnAttribute(Attribute::VScaleRange)) { | ||
| Attribute Attr = F->getFnAttribute(Attribute::VScaleRange); |
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Suggested change
| if (ScalableTy && F->hasFnAttribute(Attribute::VScaleRange)) { | |
| Attribute Attr = F->getFnAttribute(Attribute::VScaleRange); | |
| Attribute Attr = F->getFnAttribute(Attribute::VScaleRange); | |
| if (ScalableTy && Attr->isValid()) { |
| if (!VScaleMax) | ||
| break; | ||
| unsigned MaxPossibleMaskElements = | ||
| ScalableTy->getMinNumElements() * (*VScaleMax); |
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Is there a risk of overflow here?
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I guess a 64-bit value should be sufficient here since both getMinNumElements and getVScaleRangeMax return 32-bit values.
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I'm not an expert in C semantics, but I don't think this is enough to guarantee it won't overflow. If I compile C code like this:
unsigned long foo(unsigned a, unsigned b) {
return a * b;
}
to LLVM IR then it looks like this:
define dso_local range(i64 0, 4294967296) i64 @foo(i32 noundef %a, i32 noundef %b) {
entry:
%mul = mul i32 %b, %a
%conv = zext i32 %mul to i64
ret i64 %conv
}
i.e. the multiplication is still done as a 32-bit value. I think you need to do something like:
uint64_t MaxPossibleMaskElements = ScalableTy->getMinNumElements();
MaxPossibleMaskElements *= *VScaleMax;
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Makes sense, thanks for explaining. If you cast the first operand, both operands get extended before the binop:
https://godbolt.org/z/z3eqnzTT6
Co-authored-by: Nikita Popov <github@npopov.com>
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Scalable get_active_lane_mask intrinsic calls can be simplified to i1 splat (ptrue) when its constant range is larger than or equal to the maximum possible number of elements, which can be inferred from vscale_range(x, y)