[llvm] [RISCV] Align stack size down to a multiple of 16 before using cm.push/pop. (PR #86073)

[Wang Pengcheng via llvm-commits]

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@@ -554,8 +554,10 @@ void RISCVFrameLowering::emitPrologue(MachineFunction &MF,
   if (RVFI->isPushable(MF) && FirstFrameSetup != MBB.end() &&
       FirstFrameSetup->getOpcode() == RISCV::CM_PUSH) {
     // Use available stack adjustment in push instruction to allocate additional
-    // stack space.
-    uint64_t Spimm = std::min(StackSize, (uint64_t)48);
+    // stack space. Align the stack size down to a multiple of 16. This is
+    // needed for RVE.
+    // FIXME: Can we increase the stack size to a multiple of 16 insead?
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wangpc-pp wrote:

`insead`->`instead`

https://github.com/llvm/llvm-project/pull/86073