[llvm] [VPlan] Optz WidenGEP with single-scalar operands (PR #166740)

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Thu Nov 6 02:27:48 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-risc-v

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

<details>
<summary>Changes</summary>

This patch is similar to b0b4616 ([VPlan] Handle single-scalar conds in VPWidenSelectRecipe) in spirit.

---
Full diff: https://github.com/llvm/llvm-project/pull/166740.diff


4 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/VPlan.h (-6) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp (+2-2) 
- (modified) llvm/test/Transforms/LoopVectorize/RISCV/gather-scatter-cost.ll (+7-7) 
- (modified) llvm/test/Transforms/LoopVectorize/widen-gep-all-indices-invariant.ll (+4-4) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index bbb03fbdff7a2..403bd8d7d814e 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1786,12 +1786,6 @@ class LLVM_ABI_FOR_TEST VPWidenGEPRecipe : public VPRecipeWithIRFlags {
     return getOperand(I + 1)->isDefinedOutsideLoopRegions();
   }
 
-  bool areAllOperandsInvariant() const {
-    return all_of(operands(), [](VPValue *Op) {
-      return Op->isDefinedOutsideLoopRegions();
-    });
-  }
-
 public:
   VPWidenGEPRecipe(GetElementPtrInst *GEP, ArrayRef<VPValue *> Operands)
       : VPRecipeWithIRFlags(VPDef::VPWidenGEPSC, Operands, *GEP),
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index 80cd112dbcd8a..dc0b59c48d3a6 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -2507,8 +2507,8 @@ void VPWidenGEPRecipe::execute(VPTransformState &State) {
   // is vector-typed. Thus, to keep the representation compact, we only use
   // vector-typed operands for loop-varying values.
 
-  if (areAllOperandsInvariant()) {
-    // If we are vectorizing, but the GEP has only loop-invariant operands,
+  if (all_of(operands(), vputils::isSingleScalar)) {
+    // If we are vectorizing, but the GEP has only single-scalar operands,
     // the GEP we build (by only using vector-typed operands for
     // loop-varying values) would be a scalar pointer. Thus, to ensure we
     // produce a vector of pointers, we need to either arbitrarily pick an
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/gather-scatter-cost.ll b/llvm/test/Transforms/LoopVectorize/RISCV/gather-scatter-cost.ll
index 212a5c99676f4..14d2c123403f2 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/gather-scatter-cost.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/gather-scatter-cost.ll
@@ -63,7 +63,7 @@ define void @predicated_uniform_load(ptr %src, i32 %n, ptr %dst, i1 %cond) {
 ; CHECK-NEXT:    store i32 [[STORE]], ptr [[NBRBOXES]], align 4
 ; CHECK-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
 ; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp sgt i32 [[IV]], [[IBOX]]
-; CHECK-NEXT:    br i1 [[EXITCOND]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
 ;
@@ -114,7 +114,7 @@ define void @predicated_strided_store(ptr %start) {
 ; RVA23-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP3]]
 ; RVA23-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 8 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
 ; RVA23-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; RVA23-NEXT:    br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; RVA23-NEXT:    br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ; RVA23:       middle.block:
 ; RVA23-NEXT:    br label [[LOOP:%.*]]
 ; RVA23:       exit:
@@ -141,7 +141,7 @@ define void @predicated_strided_store(ptr %start) {
 ; RVA23ZVL1024B-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP3]]
 ; RVA23ZVL1024B-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
 ; RVA23ZVL1024B-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; RVA23ZVL1024B-NEXT:    br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; RVA23ZVL1024B-NEXT:    br i1 [[TMP7]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ; RVA23ZVL1024B:       middle.block:
 ; RVA23ZVL1024B-NEXT:    br label [[LOOP:%.*]]
 ; RVA23ZVL1024B:       exit:
@@ -185,16 +185,16 @@ define void @store_to_addr_generated_from_invariant_addr(ptr noalias %p0, ptr no
 ; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i32, ptr [[P1:%.*]], <vscale x 2 x i64> [[VEC_IND]]
 ; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2p0.nxv2p0(<vscale x 2 x ptr> [[BROADCAST_SPLAT1]], <vscale x 2 x ptr> align 8 [[TMP5]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP3]])
 ; CHECK-NEXT:    [[TMP6:%.*]] = load i64, ptr [[P2:%.*]], align 4
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP6]], i64 0
-; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
-; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[P3:%.*]], <vscale x 2 x i64> [[BROADCAST_SPLAT2]]
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[P3:%.*]], i64 [[TMP6]]
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 2 x ptr> poison, ptr [[TMP8]], i64 0
+; CHECK-NEXT:    [[TMP7:%.*]] = shufflevector <vscale x 2 x ptr> [[DOTSPLATINSERT]], <vscale x 2 x ptr> poison, <vscale x 2 x i32> zeroinitializer
 ; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2i32.nxv2p0(<vscale x 2 x i32> zeroinitializer, <vscale x 2 x ptr> align 4 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP3]])
 ; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2i32.nxv2p0(<vscale x 2 x i32> zeroinitializer, <vscale x 2 x ptr> align 4 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP3]])
 ; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2i8.nxv2p0(<vscale x 2 x i8> zeroinitializer, <vscale x 2 x ptr> align 1 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP3]])
 ; CHECK-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP4]]
 ; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
 ; CHECK-NEXT:    [[TMP9:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP11:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP9]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       exit:
diff --git a/llvm/test/Transforms/LoopVectorize/widen-gep-all-indices-invariant.ll b/llvm/test/Transforms/LoopVectorize/widen-gep-all-indices-invariant.ll
index d08ca8c99e8ba..c18cbde8340fa 100644
--- a/llvm/test/Transforms/LoopVectorize/widen-gep-all-indices-invariant.ll
+++ b/llvm/test/Transforms/LoopVectorize/widen-gep-all-indices-invariant.ll
@@ -55,11 +55,11 @@ define void @wide_gep_index_invariant(ptr noalias %dst, ptr noalias %src, i64 %n
 ; CHECK:       vector.body:
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
 ; CHECK-NEXT:    [[TMP0:%.*]] = load ptr, ptr [[SRC]], align 8
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x ptr> poison, ptr [[TMP0]], i64 0
-; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x ptr> [[BROADCAST_SPLATINSERT]], <4 x ptr> poison, <4 x i32> zeroinitializer
-; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr float, <4 x ptr> [[BROADCAST_SPLAT]], i64 [[N]]
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr float, ptr [[TMP0]], i64 [[N]]
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <4 x ptr> poison, ptr [[TMP1]], i64 0
+; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <4 x ptr> [[DOTSPLATINSERT]], <4 x ptr> poison, <4 x i32> zeroinitializer
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr ptr, ptr [[DST]], i64 [[INDEX]]
-; CHECK-NEXT:    store <4 x ptr> [[TMP1]], ptr [[TMP2]], align 8
+; CHECK-NEXT:    store <4 x ptr> [[DOTSPLAT]], ptr [[TMP2]], align 8
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i64 [[INDEX_NEXT]], 100
 ; CHECK-NEXT:    br i1 [[TMP3]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]

``````````

</details>


https://github.com/llvm/llvm-project/pull/166740


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