Reland [VPlan] Expand WidenInt inductions with nuw/nsw

Changes: The previous patch had to be reverted to a mismatching-OpType
assert in cse. The reduced-test has now been added corresponding to a
RVV pointer-induction, and the pointer-induction case has been updated
to use createOverflowingBinaryOp.

While at it, record VPIRFlags in VPWidenInductionRecipe.

Author: artagnon

llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h

@@ -178,11 +178,10 @@ class VPBuilder {
         new VPInstructionWithType(Opcode, Operands, ResultTy, Flags, DL, Name));
   }
 
-  VPInstruction *createOverflowingOp(unsigned Opcode,
-                                     ArrayRef<VPValue *> Operands,
-                                     VPRecipeWithIRFlags::WrapFlagsTy WrapFlags,
-                                     DebugLoc DL = DebugLoc::getUnknown(),
-                                     const Twine &Name = "") {
+  VPInstruction *createOverflowingOp(
+      unsigned Opcode, ArrayRef<VPValue *> Operands,
+      VPRecipeWithIRFlags::WrapFlagsTy WrapFlags = {false, false},
+      DebugLoc DL = DebugLoc::getUnknown(), const Twine &Name = "") {
     return tryInsertInstruction(
         new VPInstruction(Opcode, Operands, WrapFlags, {}, DL, Name));
   }

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -3413,7 +3413,7 @@ static void expandVPWidenPointerInduction(VPWidenPointerInductionRecipe *R,
   Builder.setInsertPoint(R->getParent(), R->getParent()->getFirstNonPhi());
   Type *StepTy = TypeInfo.inferScalarType(Step);
   VPValue *Offset = Builder.createNaryOp(VPInstruction::StepVector, {}, StepTy);
-  Offset = Builder.createNaryOp(Instruction::Mul, {Offset, Step});
+  Offset = Builder.createOverflowingOp(Instruction::Mul, {Offset, Step});
   VPValue *PtrAdd = Builder.createNaryOp(
       VPInstruction::WidePtrAdd, {ScalarPtrPhi, Offset}, DL, "vector.gep");
   R->replaceAllUsesWith(PtrAdd);
@@ -3423,7 +3423,7 @@ static void expandVPWidenPointerInduction(VPWidenPointerInductionRecipe *R,
   Builder.setInsertPoint(ExitingBB, ExitingBB->getTerminator()->getIterator());
   VF = Builder.createScalarZExtOrTrunc(VF, StepTy, TypeInfo.inferScalarType(VF),
                                        DL);
-  VPValue *Inc = Builder.createNaryOp(Instruction::Mul, {Step, VF});
+  VPValue *Inc = Builder.createOverflowingOp(Instruction::Mul, {Step, VF});
 
   VPValue *InductionGEP =
       Builder.createPtrAdd(ScalarPtrPhi, Inc, DL, "ptr.ind");

llvm/test/Transforms/LoopVectorize/RISCV/pointer-induction.ll

@@ -1,9 +1,48 @@
-; REQUIRES: asserts
-; RUN: not --crash opt -p loop-vectorize -S %s
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals none --version 6
+; RUN: opt -p loop-vectorize -S %s | FileCheck %s
 
 target triple = "riscv64-unknown-linux-gnu"
 
 define void @ptr_induction(ptr %p, ptr noalias %q, ptr noalias %p.end) #0 {
+; CHECK-LABEL: define void @ptr_induction(
+; CHECK-SAME: ptr [[P:%.*]], ptr noalias [[Q:%.*]], ptr noalias [[P_END:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[P2:%.*]] = ptrtoint ptr [[P]] to i64
+; CHECK-NEXT:    [[P_END1:%.*]] = ptrtoint ptr [[P_END]] to i64
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[P_END1]], 1
+; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], [[P2]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x ptr> poison, ptr [[Q]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x ptr> [[BROADCAST_SPLATINSERT]], <vscale x 2 x ptr> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 2 x ptr> poison, ptr [[P]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 2 x ptr> [[BROADCAST_SPLATINSERT3]], <vscale x 2 x ptr> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP2:%.*]] = call <vscale x 2 x i64> @llvm.stepvector.nxv2i64()
+; CHECK-NEXT:    [[TMP3:%.*]] = mul <vscale x 2 x i64> [[TMP2]], splat (i64 1)
+; CHECK-NEXT:    [[INDUCTION:%.*]] = add <vscale x 2 x i64> zeroinitializer, [[TMP3]]
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 2 x i64> [ [[INDUCTION]], %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[POINTER_PHI:%.*]] = phi ptr [ [[P]], %[[VECTOR_PH]] ], [ [[PTR_IND7:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[AVL:%.*]] = phi i64 [ [[TMP1]], %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VECTOR_GEP:%.*]] = getelementptr i8, ptr [[POINTER_PHI]], <vscale x 2 x i64> [[TMP2]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
+; CHECK-NEXT:    [[TMP5:%.*]] = zext i32 [[TMP4]] to i64
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT5:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP5]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT6:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT5]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP6:%.*]] = ptrtoint <vscale x 2 x ptr> [[VECTOR_GEP]] to <vscale x 2 x i64>
+; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2i64.nxv2p0(<vscale x 2 x i64> [[TMP6]], <vscale x 2 x ptr> align 8 [[BROADCAST_SPLAT]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP4]])
+; CHECK-NEXT:    call void @llvm.vp.scatter.nxv2i64.nxv2p0(<vscale x 2 x i64> [[VEC_IND]], <vscale x 2 x ptr> align 8 [[BROADCAST_SPLAT4]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP4]])
+; CHECK-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP5]]
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT6]]
+; CHECK-NEXT:    [[PTR_IND7]] = getelementptr i8, ptr [[POINTER_PHI]], i64 [[TMP5]]
+; CHECK-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
+; CHECK-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
 entry:
   br label %loop