Revert "[RISCV] Expand vp.stride.load to splat of a scalar load."

[nico]

Reverts #98140

Breaks tests, see comments on the PR.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Nico Weber (nico)

Changes

Reverts llvm/llvm-project#98140

Breaks tests, see comments on the PR.

---

Full diff: https://github.com/llvm/llvm-project/pull/98422.diff

3 Files Affected:

• (modified) llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp (-50)
• (modified) llvm/test/CodeGen/RISCV/rvv/fixed-vectors-strided-vpload.ll (+4-46)
• (modified) llvm/test/CodeGen/RISCV/rvv/strided-vpload.ll (+2-44)

diff --git a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
index 10e0496f16d4f..6e0f429c34b2f 100644
--- a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
+++ b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
@@ -18,11 +18,9 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
-#include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstVisitor.h"
 #include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/IntrinsicsRISCV.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
@@ -37,7 +35,6 @@ namespace {
 class RISCVCodeGenPrepare : public FunctionPass,
                             public InstVisitor<RISCVCodeGenPrepare, bool> {
   const DataLayout *DL;
-  const DominatorTree *DT;
   const RISCVSubtarget *ST;
 
 public:
@@ -51,14 +48,12 @@ class RISCVCodeGenPrepare : public FunctionPass,
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
-    AU.addRequired<DominatorTreeWrapperPass>();
     AU.addRequired<TargetPassConfig>();
   }
 
   bool visitInstruction(Instruction &I) { return false; }
   bool visitAnd(BinaryOperator &BO);
   bool visitIntrinsicInst(IntrinsicInst &I);
-  bool expandVPStrideLoad(IntrinsicInst &I);
 };
 
 } // end anonymous namespace
@@ -133,9 +128,6 @@ bool RISCVCodeGenPrepare::visitAnd(BinaryOperator &BO) {
 // Which eliminates the scalar -> vector -> scalar crossing during instruction
 // selection.
 bool RISCVCodeGenPrepare::visitIntrinsicInst(IntrinsicInst &I) {
-  if (expandVPStrideLoad(I))
-    return true;
-
   if (I.getIntrinsicID() != Intrinsic::vector_reduce_fadd)
     return false;
 
@@ -163,47 +155,6 @@ bool RISCVCodeGenPrepare::visitIntrinsicInst(IntrinsicInst &I) {
   return true;
 }
 
-bool RISCVCodeGenPrepare::expandVPStrideLoad(IntrinsicInst &II) {
-  if (ST->hasOptimizedZeroStrideLoad())
-    return false;
-
-  Value *BasePtr, *VL;
-  using namespace PatternMatch;
-  if (!match(&II, m_Intrinsic<Intrinsic::experimental_vp_strided_load>(
-                      m_Value(BasePtr), m_Zero(), m_AllOnes(), m_Value(VL))))
-    return false;
-
-  if (!isKnownNonZero(VL, {*DL, DT, nullptr, &II}))
-    return false;
-
-  auto *VTy = cast<VectorType>(II.getType());
-
-  IRBuilder<> Builder(&II);
-
-  // Extend VL from i32 to XLen if needed.
-  if (ST->is64Bit())
-    VL = Builder.CreateZExt(VL, Builder.getInt64Ty());
-
-  Type *STy = VTy->getElementType();
-  Value *Val = Builder.CreateLoad(STy, BasePtr);
-  const auto &TLI = *ST->getTargetLowering();
-  Value *Res;
-
-  // TODO: Also support fixed/illegal vector types to splat with evl = vl.
-  if (isa<ScalableVectorType>(VTy) && TLI.isTypeLegal(EVT::getEVT(VTy))) {
-    unsigned VMVOp = STy->isFloatingPointTy() ? Intrinsic::riscv_vfmv_v_f
-                                              : Intrinsic::riscv_vmv_v_x;
-    Res = Builder.CreateIntrinsic(VMVOp, {VTy, VL->getType()},
-                                  {PoisonValue::get(VTy), Val, VL});
-  } else {
-    Res = Builder.CreateVectorSplat(VTy->getElementCount(), Val);
-  }
-
-  II.replaceAllUsesWith(Res);
-  II.eraseFromParent();
-  return true;
-}
-
 bool RISCVCodeGenPrepare::runOnFunction(Function &F) {
   if (skipFunction(F))
     return false;
@@ -213,7 +164,6 @@ bool RISCVCodeGenPrepare::runOnFunction(Function &F) {
   ST = &TM.getSubtarget<RISCVSubtarget>(F);
 
   DL = &F.getDataLayout();
-  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
 
   bool MadeChange = false;
   for (auto &BB : F)
diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-strided-vpload.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-strided-vpload.ll
index 86359043a90d9..5e64e9fbc1a2f 100644
--- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-strided-vpload.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-strided-vpload.ll
@@ -1,16 +1,10 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -mattr=+m,+d,+zfh,+v,+zvfh \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV32
+; RUN:   -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,CHECK-RV32
 ; RUN: llc -mtriple=riscv64 -mattr=+m,+d,+zfh,+v,+zvfh \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV64,CHECK-OPT
-; RUN: llc -mtriple=riscv32 -mattr=+m,+d,+zfh,+v,+zvfh,+no-optimized-zero-stride-load \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV32,CHECK-NOOPT
-; RUN: llc -mtriple=riscv64 -mattr=+m,+d,+zfh,+v,+zvfh,+no-optimized-zero-stride-load  \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV64,CHECK-NOOPT
+; RUN:   -verify-machineinstrs < %s \
+; RUN:   | FileCheck %s --check-prefixes=CHECK,CHECK-RV64
 
 declare <2 x i8> @llvm.experimental.vp.strided.load.v2i8.p0.i8(ptr, i8, <2 x i1>, i32)
 
@@ -632,39 +626,3 @@ define <33 x double> @strided_load_v33f64(ptr %ptr, i64 %stride, <33 x i1> %mask
 }
 
 declare <33 x double> @llvm.experimental.vp.strided.load.v33f64.p0.i64(ptr, i64, <33 x i1>, i32)
-
-; Test unmasked integer zero strided
-define <4 x i8> @zero_strided_unmasked_vpload_4i8_i8(ptr %ptr) {
-; CHECK-OPT-LABEL: zero_strided_unmasked_vpload_4i8_i8:
-; CHECK-OPT:       # %bb.0:
-; CHECK-OPT-NEXT:    vsetivli zero, 4, e8, mf4, ta, ma
-; CHECK-OPT-NEXT:    vlse8.v v8, (a0), zero
-; CHECK-OPT-NEXT:    ret
-;
-; CHECK-NOOPT-LABEL: zero_strided_unmasked_vpload_4i8_i8:
-; CHECK-NOOPT:       # %bb.0:
-; CHECK-NOOPT-NEXT:    lbu a0, 0(a0)
-; CHECK-NOOPT-NEXT:    vsetivli zero, 4, e8, mf4, ta, ma
-; CHECK-NOOPT-NEXT:    vmv.v.x v8, a0
-; CHECK-NOOPT-NEXT:    ret
-  %load = call <4 x i8> @llvm.experimental.vp.strided.load.4i8.p0.i8(ptr %ptr, i8 0, <4 x i1> splat (i1 true), i32 4)
-  ret <4 x i8> %load
-}
-
-; Test unmasked float zero strided
-define <4 x half> @zero_strided_unmasked_vpload_4f16(ptr %ptr) {
-; CHECK-OPT-LABEL: zero_strided_unmasked_vpload_4f16:
-; CHECK-OPT:       # %bb.0:
-; CHECK-OPT-NEXT:    vsetivli zero, 4, e16, mf2, ta, ma
-; CHECK-OPT-NEXT:    vlse16.v v8, (a0), zero
-; CHECK-OPT-NEXT:    ret
-;
-; CHECK-NOOPT-LABEL: zero_strided_unmasked_vpload_4f16:
-; CHECK-NOOPT:       # %bb.0:
-; CHECK-NOOPT-NEXT:    flh fa5, 0(a0)
-; CHECK-NOOPT-NEXT:    vsetivli zero, 4, e16, mf2, ta, ma
-; CHECK-NOOPT-NEXT:    vfmv.v.f v8, fa5
-; CHECK-NOOPT-NEXT:    ret
-  %load = call <4 x half> @llvm.experimental.vp.strided.load.4f16.p0.i32(ptr %ptr, i32 0, <4 x i1> splat (i1 true), i32 4)
-  ret <4 x half> %load
-}
diff --git a/llvm/test/CodeGen/RISCV/rvv/strided-vpload.ll b/llvm/test/CodeGen/RISCV/rvv/strided-vpload.ll
index d422ed5dcfc22..4d3bced0bcb50 100644
--- a/llvm/test/CodeGen/RISCV/rvv/strided-vpload.ll
+++ b/llvm/test/CodeGen/RISCV/rvv/strided-vpload.ll
@@ -1,16 +1,10 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -mattr=+m,+d,+zfh,+v,+zvfh \
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV32,CHECK-OPT
+; RUN:     -check-prefixes=CHECK,CHECK-RV32
 ; RUN: llc -mtriple=riscv64 -mattr=+m,+d,+zfh,+v,+zvfh \
 ; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV64,CHECK-OPT
-; RUN: llc -mtriple=riscv32 -mattr=+m,+d,+zfh,+v,+zvfh,+no-optimized-zero-stride-load \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV32,CHECK-NOOPT
-; RUN: llc -mtriple=riscv64 -mattr=+m,+d,+zfh,+v,+zvfh,+no-optimized-zero-stride-load  \
-; RUN:     -verify-machineinstrs < %s | FileCheck %s \
-; RUN:     -check-prefixes=CHECK,CHECK-RV64,CHECK-NOOPT
+; RUN:     -check-prefixes=CHECK,CHECK-RV64
 
 declare <vscale x 1 x i8> @llvm.experimental.vp.strided.load.nxv1i8.p0.i8(ptr, i8, <vscale x 1 x i1>, i32)
 
@@ -786,39 +780,3 @@ define <vscale x 16 x double> @strided_load_nxv17f64(ptr %ptr, i64 %stride, <vsc
 declare <vscale x 17 x double> @llvm.experimental.vp.strided.load.nxv17f64.p0.i64(ptr, i64, <vscale x 17 x i1>, i32)
 declare <vscale x 1 x double> @llvm.experimental.vector.extract.nxv1f64(<vscale x 17 x double> %vec, i64 %idx)
 declare <vscale x 16 x double> @llvm.experimental.vector.extract.nxv16f64(<vscale x 17 x double> %vec, i64 %idx)
-
-; Test unmasked integer zero strided
-define <vscale x 1 x i8> @zero_strided_unmasked_vpload_nxv1i8_i8(ptr %ptr) {
-; CHECK-OPT-LABEL: zero_strided_unmasked_vpload_nxv1i8_i8:
-; CHECK-OPT:       # %bb.0:
-; CHECK-OPT-NEXT:    vsetivli zero, 4, e8, mf8, ta, ma
-; CHECK-OPT-NEXT:    vlse8.v v8, (a0), zero
-; CHECK-OPT-NEXT:    ret
-;
-; CHECK-NOOPT-LABEL: zero_strided_unmasked_vpload_nxv1i8_i8:
-; CHECK-NOOPT:       # %bb.0:
-; CHECK-NOOPT-NEXT:    lbu a0, 0(a0)
-; CHECK-NOOPT-NEXT:    vsetivli zero, 4, e8, mf8, ta, ma
-; CHECK-NOOPT-NEXT:    vmv.v.x v8, a0
-; CHECK-NOOPT-NEXT:    ret
-  %load = call <vscale x 1 x i8> @llvm.experimental.vp.strided.load.nxv1i8.p0.i8(ptr %ptr, i8 0, <vscale x 1 x i1> splat (i1 true), i32 4)
-  ret <vscale x 1 x i8> %load
-}
-
-; Test unmasked float zero strided
-define <vscale x 1 x half> @zero_strided_unmasked_vpload_nxv1f16(ptr %ptr) {
-; CHECK-OPT-LABEL: zero_strided_unmasked_vpload_nxv1f16:
-; CHECK-OPT:       # %bb.0:
-; CHECK-OPT-NEXT:    vsetivli zero, 4, e16, mf4, ta, ma
-; CHECK-OPT-NEXT:    vlse16.v v8, (a0), zero
-; CHECK-OPT-NEXT:    ret
-;
-; CHECK-NOOPT-LABEL: zero_strided_unmasked_vpload_nxv1f16:
-; CHECK-NOOPT:       # %bb.0:
-; CHECK-NOOPT-NEXT:    flh fa5, 0(a0)
-; CHECK-NOOPT-NEXT:    vsetivli zero, 4, e16, mf4, ta, ma
-; CHECK-NOOPT-NEXT:    vfmv.v.f v8, fa5
-; CHECK-NOOPT-NEXT:    ret
-  %load = call <vscale x 1 x half> @llvm.experimental.vp.strided.load.nxv1f16.p0.i32(ptr %ptr, i32 0, <vscale x 1 x i1> splat (i1 true), i32 4)
-  ret <vscale x 1 x half> %load
-}