[llvm] [LV][EVL] Disable fixed-order recurrence idiom with EVL tail folding. (PR #122458)

via llvm-commits llvm-commits at lists.llvm.org
Fri Jan 10 06:06:00 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Mel Chen (Mel-Chen)

<details>
<summary>Changes</summary>



---

Patch is 41.02 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/122458.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+5-3) 
- (added) llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-fixed-order-recurrence.ll (+561) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index b017b61a45a0c3..92744b3a5c7c8e 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1447,9 +1447,11 @@ class LoopVectorizationCostModel {
     // Override forced styles if needed.
     // FIXME: use actual opcode/data type for analysis here.
     // FIXME: Investigate opportunity for fixed vector factor.
-    bool EVLIsLegal = UserIC <= 1 &&
-                      TTI.hasActiveVectorLength(0, nullptr, Align()) &&
-                      !EnableVPlanNativePath;
+    bool EVLIsLegal =
+        UserIC <= 1 && TTI.hasActiveVectorLength(0, nullptr, Align()) &&
+        !EnableVPlanNativePath &&
+        // FIXME: remove this once fixed-ordered recurrence is suppored.
+        Legal->getFixedOrderRecurrences().empty();
     if (!EVLIsLegal) {
       // If for some reason EVL mode is unsupported, fallback to
       // DataWithoutLaneMask to try to vectorize the loop with folded tail
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-fixed-order-recurrence.ll b/llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-fixed-order-recurrence.ll
new file mode 100644
index 00000000000000..614c090d5666fc
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/vectorize-force-tail-with-evl-fixed-order-recurrence.ll
@@ -0,0 +1,561 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=loop-vectorize \
+; RUN: -prefer-inloop-reductions \
+; RUN: -force-tail-folding-style=data-with-evl \
+; RUN: -prefer-predicate-over-epilogue=predicate-dont-vectorize \
+; RUN: -mtriple=riscv64 -mattr=+v,+f -S < %s| FileCheck %s --check-prefix=IF-EVL
+
+; RUN: opt -passes=loop-vectorize \
+; RUN: -prefer-inloop-reductions \
+; RUN: -force-tail-folding-style=none \
+; RUN: -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue \
+; RUN: -mtriple=riscv64 -mattr=+v,+f -S < %s| FileCheck %s --check-prefix=NO-VP
+
+define void @first_order_recurrence(ptr noalias %A, ptr noalias %B, i64 %TC) {
+; IF-EVL-LABEL: define void @first_order_recurrence(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], i64 [[TC:%.*]]) #[[ATTR0:[0-9]+]] {
+; IF-EVL-NEXT:  [[ENTRY:.*]]:
+; IF-EVL-NEXT:    [[TMP0:%.*]] = sub i64 -1, [[TC]]
+; IF-EVL-NEXT:    [[TMP1:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP2:%.*]] = mul i64 [[TMP1]], 4
+; IF-EVL-NEXT:    [[TMP3:%.*]] = icmp ult i64 [[TMP0]], [[TMP2]]
+; IF-EVL-NEXT:    br i1 [[TMP3]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 4
+; IF-EVL-NEXT:    [[TMP6:%.*]] = sub i64 [[TMP5]], 1
+; IF-EVL-NEXT:    [[N_RND_UP:%.*]] = add i64 [[TC]], [[TMP6]]
+; IF-EVL-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], [[TMP5]]
+; IF-EVL-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
+; IF-EVL-NEXT:    [[TRIP_COUNT_MINUS_1:%.*]] = sub i64 [[TC]], 1
+; IF-EVL-NEXT:    [[TMP7:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP8:%.*]] = mul i64 [[TMP7]], 4
+; IF-EVL-NEXT:    [[TMP9:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP10:%.*]] = mul i32 [[TMP9]], 4
+; IF-EVL-NEXT:    [[TMP11:%.*]] = sub i32 [[TMP10]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 33, i32 [[TMP11]]
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[TRIP_COUNT_MINUS_1]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 4 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[VP_OP_LOAD:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP13:%.*]] = add i64 [[EVL_BASED_IV]], 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[EVL_BASED_IV]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
+; IF-EVL-NEXT:    [[TMP25:%.*]] = call <vscale x 4 x i64> @llvm.stepvector.nxv4i64()
+; IF-EVL-NEXT:    [[TMP26:%.*]] = add <vscale x 4 x i64> zeroinitializer, [[TMP25]]
+; IF-EVL-NEXT:    [[VEC_IV:%.*]] = add <vscale x 4 x i64> [[BROADCAST_SPLAT]], [[TMP26]]
+; IF-EVL-NEXT:    [[TMP27:%.*]] = icmp ule <vscale x 4 x i64> [[VEC_IV]], [[BROADCAST_SPLAT2]]
+; IF-EVL-NEXT:    [[TMP14:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[TMP13]]
+; IF-EVL-NEXT:    [[TMP15:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP14]], i32 0
+; IF-EVL-NEXT:    [[VP_OP_LOAD]] = call <vscale x 4 x i32> @llvm.masked.load.nxv4i32.p0(ptr [[TMP15]], i32 4, <vscale x 4 x i1> [[TMP27]], <vscale x 4 x i32> poison)
+; IF-EVL-NEXT:    [[TMP16:%.*]] = call <vscale x 4 x i32> @llvm.vector.splice.nxv4i32(<vscale x 4 x i32> [[VECTOR_RECUR]], <vscale x 4 x i32> [[VP_OP_LOAD]], i32 -1)
+; IF-EVL-NEXT:    [[TMP19:%.*]] = add nsw <vscale x 4 x i32> [[TMP16]], [[VP_OP_LOAD]]
+; IF-EVL-NEXT:    [[TMP17:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[TMP13]]
+; IF-EVL-NEXT:    [[TMP18:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP17]], i32 0
+; IF-EVL-NEXT:    call void @llvm.masked.store.nxv4i32.p0(<vscale x 4 x i32> [[TMP19]], ptr [[TMP18]], i32 4, <vscale x 4 x i1> [[TMP27]])
+; IF-EVL-NEXT:    [[INDEX_NEXT]] = add i64 [[EVL_BASED_IV]], [[TMP8]]
+; IF-EVL-NEXT:    [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; IF-EVL-NEXT:    br i1 [[TMP20]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    [[TMP21:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP22:%.*]] = mul i32 [[TMP21]], 4
+; IF-EVL-NEXT:    [[TMP23:%.*]] = sub i32 [[TMP22]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <vscale x 4 x i32> [[VP_OP_LOAD]], i32 [[TMP23]]
+; IF-EVL-NEXT:    br i1 true, label %[[FOR_END:.*]], label %[[SCALAR_PH]]
+; IF-EVL:       [[SCALAR_PH]]:
+; IF-EVL-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; IF-EVL-NEXT:    [[SCALAR_RECUR_INIT:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT]], %[[MIDDLE_BLOCK]] ], [ 33, %[[ENTRY]] ]
+; IF-EVL-NEXT:    br label %[[FOR_BODY:.*]]
+; IF-EVL:       [[FOR_BODY]]:
+; IF-EVL-NEXT:    [[INDVARS:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INDVARS_NEXT:%.*]], %[[FOR_BODY]] ]
+; IF-EVL-NEXT:    [[FOR1:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT]], %[[SCALAR_PH]] ], [ [[TMP24:%.*]], %[[FOR_BODY]] ]
+; IF-EVL-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[INDVARS]]
+; IF-EVL-NEXT:    [[TMP24]] = load i32, ptr [[ARRAYIDX]], align 4
+; IF-EVL-NEXT:    [[ADD:%.*]] = add nsw i32 [[FOR1]], [[TMP24]]
+; IF-EVL-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[INDVARS]]
+; IF-EVL-NEXT:    store i32 [[ADD]], ptr [[ARRAYIDX2]], align 4
+; IF-EVL-NEXT:    [[INDVARS_NEXT]] = add nuw nsw i64 [[INDVARS]], 1
+; IF-EVL-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_NEXT]], [[TC]]
+; IF-EVL-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_END]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; IF-EVL:       [[FOR_END]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @first_order_recurrence(
+; NO-VP-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], i64 [[TC:%.*]]) #[[ATTR0:[0-9]+]] {
+; NO-VP-NEXT:  [[ENTRY:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = mul i64 [[TMP0]], 4
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TC]], [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul i64 [[TMP2]], 4
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TC]], [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 [[TC]], [[N_MOD_VF]]
+; NO-VP-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 4
+; NO-VP-NEXT:    [[TMP6:%.*]] = call i32 @llvm.vscale.i32()
+; NO-VP-NEXT:    [[TMP7:%.*]] = mul i32 [[TMP6]], 4
+; NO-VP-NEXT:    [[TMP8:%.*]] = sub i32 [[TMP7]], 1
+; NO-VP-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 33, i32 [[TMP8]]
+; NO-VP-NEXT:    br label %[[VECTOR_BODY:.*]]
+; NO-VP:       [[VECTOR_BODY]]:
+; NO-VP-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[WIDE_LOAD:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[TMP9:%.*]] = add i64 [[INDEX]], 0
+; NO-VP-NEXT:    [[TMP10:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[TMP9]]
+; NO-VP-NEXT:    [[TMP11:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP10]], i32 0
+; NO-VP-NEXT:    [[WIDE_LOAD]] = load <vscale x 4 x i32>, ptr [[TMP11]], align 4
+; NO-VP-NEXT:    [[TMP12:%.*]] = call <vscale x 4 x i32> @llvm.vector.splice.nxv4i32(<vscale x 4 x i32> [[VECTOR_RECUR]], <vscale x 4 x i32> [[WIDE_LOAD]], i32 -1)
+; NO-VP-NEXT:    [[TMP13:%.*]] = add nsw <vscale x 4 x i32> [[TMP12]], [[WIDE_LOAD]]
+; NO-VP-NEXT:    [[TMP14:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[TMP9]]
+; NO-VP-NEXT:    [[TMP15:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP14]], i32 0
+; NO-VP-NEXT:    store <vscale x 4 x i32> [[TMP13]], ptr [[TMP15]], align 4
+; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; NO-VP-NEXT:    [[TMP16:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[TMP16]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; NO-VP:       [[MIDDLE_BLOCK]]:
+; NO-VP-NEXT:    [[TMP17:%.*]] = call i32 @llvm.vscale.i32()
+; NO-VP-NEXT:    [[TMP18:%.*]] = mul i32 [[TMP17]], 4
+; NO-VP-NEXT:    [[TMP19:%.*]] = sub i32 [[TMP18]], 1
+; NO-VP-NEXT:    [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <vscale x 4 x i32> [[WIDE_LOAD]], i32 [[TMP19]]
+; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TC]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[FOR_END:.*]], label %[[SCALAR_PH]]
+; NO-VP:       [[SCALAR_PH]]:
+; NO-VP-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; NO-VP-NEXT:    [[SCALAR_RECUR_INIT:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT]], %[[MIDDLE_BLOCK]] ], [ 33, %[[ENTRY]] ]
+; NO-VP-NEXT:    br label %[[FOR_BODY:.*]]
+; NO-VP:       [[FOR_BODY]]:
+; NO-VP-NEXT:    [[INDVARS:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INDVARS_NEXT:%.*]], %[[FOR_BODY]] ]
+; NO-VP-NEXT:    [[FOR1:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT]], %[[SCALAR_PH]] ], [ [[TMP20:%.*]], %[[FOR_BODY]] ]
+; NO-VP-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[INDVARS]]
+; NO-VP-NEXT:    [[TMP20]] = load i32, ptr [[ARRAYIDX]], align 4
+; NO-VP-NEXT:    [[ADD:%.*]] = add nsw i32 [[FOR1]], [[TMP20]]
+; NO-VP-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[INDVARS]]
+; NO-VP-NEXT:    store i32 [[ADD]], ptr [[ARRAYIDX2]], align 4
+; NO-VP-NEXT:    [[INDVARS_NEXT]] = add nuw nsw i64 [[INDVARS]], 1
+; NO-VP-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_NEXT]], [[TC]]
+; NO-VP-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_END]], label %[[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; NO-VP:       [[FOR_END]]:
+; NO-VP-NEXT:    ret void
+;
+entry:
+  br label %for.body
+
+for.body:
+  %indvars = phi i64 [ 0, %entry ], [ %indvars.next, %for.body ]
+  %for1 = phi i32 [ 33, %entry ], [ %0, %for.body ]
+  %arrayidx = getelementptr inbounds nuw i32, ptr %A, i64 %indvars
+  %0 = load i32, ptr %arrayidx, align 4
+  %add = add nsw i32 %for1, %0
+  %arrayidx2 = getelementptr inbounds nuw i32, ptr %B, i64 %indvars
+  store i32 %add, ptr %arrayidx2, align 4
+  %indvars.next = add nuw nsw i64 %indvars, 1
+  %exitcond.not = icmp eq i64 %indvars.next, %TC
+  br i1 %exitcond.not, label %for.end, label %for.body, !llvm.loop !0
+
+for.end:
+  ret void
+}
+
+define void @second_order_recurrence(ptr noalias %A, ptr noalias %B, i64 %TC) {
+; IF-EVL-LABEL: define void @second_order_recurrence(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], i64 [[TC:%.*]]) #[[ATTR0]] {
+; IF-EVL-NEXT:  [[ENTRY:.*]]:
+; IF-EVL-NEXT:    [[TMP0:%.*]] = sub i64 -1, [[TC]]
+; IF-EVL-NEXT:    [[TMP1:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP2:%.*]] = mul i64 [[TMP1]], 4
+; IF-EVL-NEXT:    [[TMP3:%.*]] = icmp ult i64 [[TMP0]], [[TMP2]]
+; IF-EVL-NEXT:    br i1 [[TMP3]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 4
+; IF-EVL-NEXT:    [[TMP6:%.*]] = sub i64 [[TMP5]], 1
+; IF-EVL-NEXT:    [[N_RND_UP:%.*]] = add i64 [[TC]], [[TMP6]]
+; IF-EVL-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N_RND_UP]], [[TMP5]]
+; IF-EVL-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
+; IF-EVL-NEXT:    [[TRIP_COUNT_MINUS_1:%.*]] = sub i64 [[TC]], 1
+; IF-EVL-NEXT:    [[TMP7:%.*]] = call i64 @llvm.vscale.i64()
+; IF-EVL-NEXT:    [[TMP8:%.*]] = mul i64 [[TMP7]], 4
+; IF-EVL-NEXT:    [[TMP9:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP10:%.*]] = mul i32 [[TMP9]], 4
+; IF-EVL-NEXT:    [[TMP11:%.*]] = sub i32 [[TMP10]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_INIT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 33, i32 [[TMP11]]
+; IF-EVL-NEXT:    [[TMP12:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP13:%.*]] = mul i32 [[TMP12]], 4
+; IF-EVL-NEXT:    [[TMP14:%.*]] = sub i32 [[TMP13]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_INIT1:%.*]] = insertelement <vscale x 4 x i32> poison, i32 22, i32 [[TMP14]]
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[TRIP_COUNT_MINUS_1]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 4 x i64> [[BROADCAST_SPLATINSERT3]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[VECTOR_RECUR:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT]], %[[VECTOR_PH]] ], [ [[VP_OP_LOAD:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[VECTOR_RECUR2:%.*]] = phi <vscale x 4 x i32> [ [[VECTOR_RECUR_INIT1]], %[[VECTOR_PH]] ], [ [[TMP19:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP16:%.*]] = add i64 [[EVL_BASED_IV]], 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[EVL_BASED_IV]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
+; IF-EVL-NEXT:    [[TMP32:%.*]] = call <vscale x 4 x i64> @llvm.stepvector.nxv4i64()
+; IF-EVL-NEXT:    [[TMP33:%.*]] = add <vscale x 4 x i64> zeroinitializer, [[TMP32]]
+; IF-EVL-NEXT:    [[VEC_IV:%.*]] = add <vscale x 4 x i64> [[BROADCAST_SPLAT]], [[TMP33]]
+; IF-EVL-NEXT:    [[TMP34:%.*]] = icmp ule <vscale x 4 x i64> [[VEC_IV]], [[BROADCAST_SPLAT4]]
+; IF-EVL-NEXT:    [[TMP17:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[TMP16]]
+; IF-EVL-NEXT:    [[TMP18:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP17]], i32 0
+; IF-EVL-NEXT:    [[VP_OP_LOAD]] = call <vscale x 4 x i32> @llvm.masked.load.nxv4i32.p0(ptr [[TMP18]], i32 4, <vscale x 4 x i1> [[TMP34]], <vscale x 4 x i32> poison)
+; IF-EVL-NEXT:    [[TMP19]] = call <vscale x 4 x i32> @llvm.vector.splice.nxv4i32(<vscale x 4 x i32> [[VECTOR_RECUR]], <vscale x 4 x i32> [[VP_OP_LOAD]], i32 -1)
+; IF-EVL-NEXT:    [[TMP20:%.*]] = call <vscale x 4 x i32> @llvm.vector.splice.nxv4i32(<vscale x 4 x i32> [[VECTOR_RECUR2]], <vscale x 4 x i32> [[TMP19]], i32 -1)
+; IF-EVL-NEXT:    [[TMP23:%.*]] = add nsw <vscale x 4 x i32> [[TMP19]], [[TMP20]]
+; IF-EVL-NEXT:    [[TMP21:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[TMP16]]
+; IF-EVL-NEXT:    [[TMP22:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP21]], i32 0
+; IF-EVL-NEXT:    call void @llvm.masked.store.nxv4i32.p0(<vscale x 4 x i32> [[TMP23]], ptr [[TMP22]], i32 4, <vscale x 4 x i1> [[TMP34]])
+; IF-EVL-NEXT:    [[INDEX_NEXT]] = add i64 [[EVL_BASED_IV]], [[TMP8]]
+; IF-EVL-NEXT:    [[TMP24:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; IF-EVL-NEXT:    br i1 [[TMP24]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    [[TMP25:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP26:%.*]] = mul i32 [[TMP25]], 4
+; IF-EVL-NEXT:    [[TMP27:%.*]] = sub i32 [[TMP26]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <vscale x 4 x i32> [[VP_OP_LOAD]], i32 [[TMP27]]
+; IF-EVL-NEXT:    [[TMP28:%.*]] = call i32 @llvm.vscale.i32()
+; IF-EVL-NEXT:    [[TMP29:%.*]] = mul i32 [[TMP28]], 4
+; IF-EVL-NEXT:    [[TMP30:%.*]] = sub i32 [[TMP29]], 1
+; IF-EVL-NEXT:    [[VECTOR_RECUR_EXTRACT3:%.*]] = extractelement <vscale x 4 x i32> [[TMP19]], i32 [[TMP30]]
+; IF-EVL-NEXT:    br i1 true, label %[[FOR_END:.*]], label %[[SCALAR_PH]]
+; IF-EVL:       [[SCALAR_PH]]:
+; IF-EVL-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[ENTRY]] ]
+; IF-EVL-NEXT:    [[SCALAR_RECUR_INIT:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT]], %[[MIDDLE_BLOCK]] ], [ 33, %[[ENTRY]] ]
+; IF-EVL-NEXT:    [[SCALAR_RECUR_INIT6:%.*]] = phi i32 [ [[VECTOR_RECUR_EXTRACT3]], %[[MIDDLE_BLOCK]] ], [ 22, %[[ENTRY]] ]
+; IF-EVL-NEXT:    br label %[[FOR_BODY:.*]]
+; IF-EVL:       [[FOR_BODY]]:
+; IF-EVL-NEXT:    [[INDVARS:%.*]] = phi i64 [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ], [ [[INDVARS_NEXT:%.*]], %[[FOR_BODY]] ]
+; IF-EVL-NEXT:    [[FOR1:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT]], %[[SCALAR_PH]] ], [ [[TMP31:%.*]], %[[FOR_BODY]] ]
+; IF-EVL-NEXT:    [[FOR2:%.*]] = phi i32 [ [[SCALAR_RECUR_INIT6]], %[[SCALAR_PH]] ], [ [[FOR1]], %[[FOR_BODY]] ]
+; IF-EVL-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds nuw i32, ptr [[A]], i64 [[INDVARS]]
+; IF-EVL-NEXT:    [[TMP31]] = load i32, ptr [[ARRAYIDX]], align 4
+; IF-EVL-NEXT:    [[ADD:%.*]] = add nsw i32 [[FOR1]], [[FOR2]]
+; IF-EVL-NEXT:    [[ARRAYIDX2:%.*]] = getelementptr inbounds nuw i32, ptr [[B]], i64 [[INDVARS]]
+; IF-EVL-NEXT:    store i32 [[ADD]], ptr [[ARRAYIDX2]], align 4
+; IF-EVL-NEXT:    [[INDVARS_NEXT]] = add nuw nsw i64 [[INDVARS]], 1
+; IF-EVL-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INDVARS_NEXT]], [[TC]]
+; IF-EVL-NEXT:    br i1 [[EXITCOND_NOT]], label %[[FOR_END]], label %[[FOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; IF-EVL:       [[FOR_END]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @second_order_recurrence(
+; NO-VP-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], i64 [[TC:%.*]]) #[[ATTR0]] {
+; NO-VP-NEXT:  [[ENTRY:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = mul i64 [[TMP0]], 4
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TC]], [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul i64 [[TMP2]], 4
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TC]], [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 [[TC]], [[N_MOD_VF]]
+; NO-VP-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 4
+; NO-VP-NEXT:    [[TMP6:%.*]] = call i32 @llvm.vscale.i32()
+; NO-VP-NEXT:    [[TMP7:%.*]] = mul i32 [[TMP6]], 4
+; NO-VP-NEXT:    [[TMP8:%.*]] = sub i32 [[TMP7]], 1
+; NO-VP-NEXT:    [[VECTOR_RECUR_INI...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/122458


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