[PowerPC] Fix the incorrect 'RM' flag set on load/store instr

[steven.zhang]

Summary

The 'RM' flag model the "Rounding Mode" and it has nothing to do with the load/store instructions.

[jsji]

LGTM.

llvm/lib/Target/PowerPC/PPCInstrVSX.td

 def HasVSX : Predicate<"PPCSubTarget->hasVSX()">;
 def IsLittleEndian : Predicate<"PPCSubTarget->isLittleEndian()">;
 def IsBigEndian : Predicate<"!PPCSubTarget->isLittleEndian()">;
 def HasOnlySwappingMemOps : Predicate<"!PPCSubTarget->hasP9Vector()">;
 
 let Predicates = [HasVSX] in {
 let AddedComplexity = 400 in { // Prefer VSX patterns over non-VSX patterns.
 let hasSideEffects = 0 in { // VSX instructions don't have side effects.
-let Uses = [RM] in {
 
   // Load indexed instructions
   let mayLoad = 1, mayStore = 0 in {
     let CodeSize = 3 in
     def LXSDX : XX1Form_memOp<31, 588,
                         (outs vsfrc:$XT), (ins memrr:$src),
                         "lxsdx $XT, $src", IIC_LdStLFD,
                         []>;
let mayStore = 1, mayLoad = 0 in {
 
     def STXVW4X : XX1Form_memOp<31, 908,
                          (outs), (ins vsrc:$XT, memrr:$dst),
                          "stxvw4x $XT, $dst", IIC_LdStSTFD,
                          []>;
     }
   } // mayStore
 
+  let Uses = [RM] in {
   // Add/Mul Instructions
   let isCommutable = 1 in {
     def XSADDDP : XX3Form<60, 32,
                           (outs vsfrc:$XT), (ins vsfrc:$XA, vsfrc:$XB),
                           "xsadddp $XT, $XA, $XB", IIC_VecFP,
                           [(set f64:$XT, (fadd f64:$XA, f64:$XB))]>;
     def XSMULDP : XX3Form<60, 48,
                           (outs vsfrc:$XT), (ins vsfrc:$XA, vsfrc:$XB),

llvm/test/CodeGen/PowerPC/instr-properties.ll

+; RUN: llc < %s -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 -verify-misched -stop-after=machine-scheduler -o - | FileCheck %s --check-prefix=CHECK-P8
+
+; Verify XFLOADf64 didn't implict def 'rm'.
+define double @rm() {
+; CHECK-P8-LABEL: bb.0.entry
+; CHECK-P8: %{{[0-9]+}}:vsfrc = XFLOADf64 $zero8, %{{[0-9]+}} ::
+entry:
+  ret double 2.300000e+00
+}