[RISCV] Use getSignedConstant for negative values.

The APInt constructor asserts if bits are set past the size of the
APInt unless it is signed.

Author: topperc

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -16353,7 +16353,7 @@ static SDValue performVP_REVERSECombine(SDNode *N, SelectionDAG &DAG,
   SDValue Temp2 = DAG.getNode(ISD::MUL, DL, XLenVT, Temp1,
                               DAG.getConstant(ElemWidthByte, DL, XLenVT));
   SDValue Base = DAG.getNode(ISD::ADD, DL, XLenVT, VPLoad->getBasePtr(), Temp2);
-  SDValue Stride = DAG.getConstant(-ElemWidthByte, DL, XLenVT);
+  SDValue Stride = DAG.getSignedConstant(-ElemWidthByte, DL, XLenVT);
 
   MachineFunction &MF = DAG.getMachineFunction();
   MachinePointerInfo PtrInfo(VPLoad->getAddressSpace());
@@ -16414,7 +16414,7 @@ static SDValue performVP_STORECombine(SDNode *N, SelectionDAG &DAG,
                               DAG.getConstant(ElemWidthByte, DL, XLenVT));
   SDValue Base =
       DAG.getNode(ISD::ADD, DL, XLenVT, VPStore->getBasePtr(), Temp2);
-  SDValue Stride = DAG.getConstant(-ElemWidthByte, DL, XLenVT);
+  SDValue Stride = DAG.getSignedConstant(-ElemWidthByte, DL, XLenVT);
 
   MachineFunction &MF = DAG.getMachineFunction();
   MachinePointerInfo PtrInfo(VPStore->getAddressSpace());

llvm/test/CodeGen/RISCV/rvv/vp-combine-reverse-load.ll

@@ -1,4 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -mattr=+f,+v -verify-machineinstrs < %s | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+f,+v -verify-machineinstrs < %s | FileCheck %s
 
 define <vscale x 2 x float> @test_reverse_load_combiner(<vscale x 2 x float>* %ptr, i32 zeroext %evl) {

llvm/test/CodeGen/RISCV/rvv/vp-combine-store-reverse.ll

@@ -1,4 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -mattr=+f,+v -verify-machineinstrs < %s | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+f,+v -verify-machineinstrs < %s | FileCheck %s
 
 define void @test_store_reverse_combiner(<vscale x 2 x float> %val, <vscale x 2 x float>* %ptr, i32 zeroext %evl) {