[RISCV] Preserve fast math flags in lowerVPOp.

[craig.topper]

Summary

Update test to check MIR after finalize-isel instead of debug output.

This is of course not the only place we should preserve FMF, but
it's the most obvious one.

[frasercrmck]

LGTM

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

for (const auto &OpIdx : enumerate(Op->ops())) {
     MVT OpVT = V.getSimpleValueType();
     MVT ContainerVT = getContainerForFixedLengthVector(OpVT);
     assert(useRVVForFixedLengthVectorVT(OpVT) &&
            "Only fixed length vectors are supported!");
     Ops.push_back(convertToScalableVector(ContainerVT, V, DAG, Subtarget));
   }
 
   if (!VT.isFixedLengthVector())
-    return DAG.getNode(RISCVISDOpc, DL, VT, Ops);
+    return DAG.getNode(RISCVISDOpc, DL, VT, Ops, Op->getFlags());
 
   MVT ContainerVT = getContainerForFixedLengthVector(VT);
 
-  SDValue VPOp = DAG.getNode(RISCVISDOpc, DL, ContainerVT, Ops);
+  SDValue VPOp = DAG.getNode(RISCVISDOpc, DL, ContainerVT, Ops, Op->getFlags());
 
   return convertFromScalableVector(VT, VPOp, DAG, Subtarget);
 }
 
 SDValue RISCVTargetLowering::lowerVPExtMaskOp(SDValue Op,
                                               SelectionDAG &DAG) const {
   SDLoc DL(Op);
   MVT VT = Op.getSimpleValueType();

llvm/test/CodeGen/RISCV/pass-fast-math-flags-sdnode.ll

-; REQUIRES: asserts
-; RUN: llc < %s -mtriple=riscv64 -mattr=+v -debug-only=isel -o /dev/null 2>&1                        | FileCheck %s
-declare <vscale x 1 x double> @llvm.vp.fmul.nxv1f64(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x i1> %m, i32 %vl)
-
-define <vscale x 1 x double> @foo(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x double> %z, <vscale x 1 x i1> %m, i32 %vl) {
-; CHECK:      t14: nxv1f64 = vp_fmul nnan ninf nsz arcp contract afn reassoc t2, t4, t8, t13
-  %1 = call fast <vscale x 1 x double> @llvm.vp.fmul.nxv1f64(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x i1> %m, i32 %vl)
-  ret <vscale x 1 x double> %1
-}

llvm/test/CodeGen/RISCV/rvv/pass-fast-math-flags-sdnode.ll

+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc < %s -mtriple=riscv64 -mattr=+v -stop-after=finalize-isel | FileCheck %s
+
+declare <vscale x 1 x double> @llvm.vp.fmul.nxv1f64(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x i1> %m, i32 %vl)
+
+define <vscale x 1 x double> @foo(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x double> %z, <vscale x 1 x i1> %m, i32 %vl) {
+  ; CHECK-LABEL: name: foo
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK-NEXT:   liveins: $v8, $v9, $v0, $x10
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:gpr = COPY $x10
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:vr = COPY $v0
+  ; CHECK-NEXT:   [[COPY2:%[0-9]+]]:vr = COPY $v9
+  ; CHECK-NEXT:   [[COPY3:%[0-9]+]]:vr = COPY $v8
+  ; CHECK-NEXT:   [[SLLI:%[0-9]+]]:gpr = SLLI [[COPY]], 32
+  ; CHECK-NEXT:   [[SRLI:%[0-9]+]]:gprnox0 = SRLI killed [[SLLI]], 32
+  ; CHECK-NEXT:   $v0 = COPY [[COPY1]]
+  ; CHECK-NEXT:   [[DEF:%[0-9]+]]:vrnov0 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %7:vrnov0 = nnan ninf nsz arcp contract afn reassoc nofpexcept PseudoVFMUL_VV_M1_MASK [[DEF]], [[COPY3]], [[COPY2]], $v0, killed [[SRLI]], 6 /* e64 */, 1, implicit $frm
+  ; CHECK-NEXT:   $v8 = COPY %7
+  ; CHECK-NEXT:   PseudoRET implicit $v8
+  %1 = call fast <vscale x 1 x double> @llvm.vp.fmul.nxv1f64(<vscale x 1 x double> %x, <vscale x 1 x double> %y, <vscale x 1 x i1> %m, i32 %vl)
+  ret <vscale x 1 x double> %1
+}