[llvm] [VPlan] Remove loop region in simplifyBranchConditionForVFAndUF with EVL PHI (PR #150016)
via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 22 06:12:02 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-risc-v
Author: Luke Lau (lukel97)
<details>
<summary>Changes</summary>
Previously we falled back to just simplifying the branch cond to true since one of the phis was a VPEVLBasedIVPHIRecipe. However this should be fine to replace with its start value.
---
Full diff: https://github.com/llvm/llvm-project/pull/150016.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+3-3)
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll (+13-20)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 2a920832f272f..cb370fe0e5b65 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1481,9 +1481,9 @@ static bool simplifyBranchConditionForVFAndUF(VPlan &Plan, ElementCount BestVF,
// (BranchOnCond true).
auto *Header = cast<VPBasicBlock>(VectorRegion->getEntry());
auto *CanIVTy = Plan.getCanonicalIV()->getScalarType();
- if (all_of(
- Header->phis(),
- IsaPred<VPCanonicalIVPHIRecipe, VPFirstOrderRecurrencePHIRecipe>)) {
+ if (all_of(Header->phis(),
+ IsaPred<VPCanonicalIVPHIRecipe, VPEVLBasedIVPHIRecipe,
+ VPFirstOrderRecurrencePHIRecipe>)) {
for (VPRecipeBase &HeaderR : make_early_inc_range(Header->phis())) {
auto *HeaderPhiR = cast<VPHeaderPHIRecipe>(&HeaderR);
HeaderPhiR->replaceAllUsesWith(HeaderPhiR->getStartValue());
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll b/llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll
index c5144645269da..e7484c6f761c0 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/low-trip-count.ll
@@ -133,23 +133,16 @@ define void @trip8_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: [[TMP4:%.*]] = mul nuw i64 [[TMP3]], 4
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
-; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[EVL_BASED_IV:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[AVL:%.*]] = sub i64 8, [[EVL_BASED_IV]]
-; CHECK-NEXT: [[TMP5:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 4, i1 true)
-; CHECK-NEXT: [[TMP8:%.*]] = getelementptr inbounds i8, ptr [[SRC:%.*]], i64 [[EVL_BASED_IV]]
-; CHECK-NEXT: [[TMP9:%.*]] = getelementptr inbounds i8, ptr [[TMP8]], i32 0
+; CHECK-NEXT: [[TMP5:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 8, i32 4, i1 true)
+; CHECK-NEXT: [[TMP9:%.*]] = getelementptr inbounds i8, ptr [[TMP8:%.*]], i32 0
; CHECK-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <vscale x 4 x i8> @llvm.vp.load.nxv4i8.p0(ptr align 1 [[TMP9]], <vscale x 4 x i1> splat (i1 true), i32 [[TMP5]])
; CHECK-NEXT: [[TMP10:%.*]] = shl <vscale x 4 x i8> [[WIDE_MASKED_LOAD]], splat (i8 1)
-; CHECK-NEXT: [[TMP11:%.*]] = getelementptr inbounds i8, ptr [[DST:%.*]], i64 [[EVL_BASED_IV]]
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i8, ptr [[TMP11]], i32 0
+; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i8, ptr [[TMP11:%.*]], i32 0
; CHECK-NEXT: [[WIDE_MASKED_LOAD1:%.*]] = call <vscale x 4 x i8> @llvm.vp.load.nxv4i8.p0(ptr align 1 [[TMP12]], <vscale x 4 x i1> splat (i1 true), i32 [[TMP5]])
; CHECK-NEXT: [[TMP13:%.*]] = add <vscale x 4 x i8> [[TMP10]], [[WIDE_MASKED_LOAD1]]
-; CHECK-NEXT: call void @llvm.vp.store.nxv4i8.p0(<vscale x 4 x i8> [[TMP13]], ptr align 1 [[TMP12]], <vscale x 4 x i1> splat (i1 true), i32 [[TMP5]])
-; CHECK-NEXT: [[TMP14:%.*]] = zext i32 [[TMP5]] to i64
-; CHECK-NEXT: [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP14]], [[EVL_BASED_IV]]
-; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP4]]
-; CHECK-NEXT: br i1 true, label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK-NEXT: [[TMP14:%.*]] = getelementptr inbounds i8, ptr [[TMP11]], i32 0
+; CHECK-NEXT: call void @llvm.vp.store.nxv4i8.p0(<vscale x 4 x i8> [[TMP13]], ptr align 1 [[TMP14]], <vscale x 4 x i1> splat (i1 true), i32 [[TMP5]])
+; CHECK-NEXT: br label [[MIDDLE_BLOCK:%.*]]
; CHECK: middle.block:
; CHECK-NEXT: br label [[FOR_END:%.*]]
; CHECK: scalar.ph:
@@ -157,16 +150,16 @@ define void @trip8_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[I_08:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
-; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[SRC]], i64 [[I_08]]
+; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i8, ptr [[TMP8]], i64 [[I_08]]
; CHECK-NEXT: [[TMP15:%.*]] = load i8, ptr [[ARRAYIDX]], align 1
; CHECK-NEXT: [[MUL:%.*]] = shl i8 [[TMP15]], 1
-; CHECK-NEXT: [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[DST]], i64 [[I_08]]
+; CHECK-NEXT: [[ARRAYIDX1:%.*]] = getelementptr inbounds i8, ptr [[TMP11]], i64 [[I_08]]
; CHECK-NEXT: [[TMP16:%.*]] = load i8, ptr [[ARRAYIDX1]], align 1
; CHECK-NEXT: [[ADD:%.*]] = add i8 [[MUL]], [[TMP16]]
; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX1]], align 1
; CHECK-NEXT: [[INC]] = add nuw nsw i64 [[I_08]], 1
; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 8
-; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -222,7 +215,7 @@ define void @trip16_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX1]], align 1
; CHECK-NEXT: [[INC]] = add nuw nsw i64 [[I_08]], 1
; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 16
-; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -279,7 +272,7 @@ define void @trip32_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX1]], align 1
; CHECK-NEXT: [[INC]] = add nuw nsw i64 [[I_08]], 1
; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 32
-; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -322,7 +315,7 @@ define void @trip24_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: store <8 x i8> [[TMP6]], ptr [[TMP5]], align 1
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 8
; CHECK-NEXT: [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], 24
-; CHECK-NEXT: br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: br i1 true, label [[FOR_END:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
@@ -339,7 +332,7 @@ define void @trip24_i8(ptr noalias nocapture noundef %dst, ptr noalias nocapture
; CHECK-NEXT: store i8 [[ADD]], ptr [[ARRAYIDX1]], align 1
; CHECK-NEXT: [[INC]] = add nuw nsw i64 [[I_08]], 1
; CHECK-NEXT: [[EXITCOND_NOT:%.*]] = icmp eq i64 [[INC]], 24
-; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK-NEXT: br i1 [[EXITCOND_NOT]], label [[FOR_END]], label [[FOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
``````````
</details>
https://github.com/llvm/llvm-project/pull/150016
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