[llvm] [RISCV] SiFive7 VLDS Sched should not depend on VL when stride is x0. (PR #70266)

[Wang Pengcheng via llvm-commits]

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@@ -455,11 +455,20 @@ foreach mx = SchedMxList in {
 // specific suffixes, but since SEW is already encoded in the name of the
 // resource, we do not need to use LMULSEWXXX constructors. However, we do
 // use the SEW from the name to determine the number of Cycles.
+
+// This predicate is true when the rs2 operand of vlse or vsse is x0, false
+// otherwise.
+def VLDSX0Pred : MCSchedPredicate<CheckRegOperand<3, X0>>;
+
 foreach mx = SchedMxList in {
+  defvar VLDSX0Cycles = SiFive7GetCyclesDefault<mx>.c;
   defvar Cycles = SiFive7GetCyclesOnePerElement<mx, 8>.c;
   defvar IsWorstCase = SiFive7IsWorstCaseMX<mx, SchedMxList>.c;
+  defm "SiFive7" : LMULWriteResMXVariant<"WriteVLDS8",  VLDSX0Pred, [SiFive7VL],
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wangpc-pp wrote:

We can drop these quotations.

https://github.com/llvm/llvm-project/pull/70266