[VE] Support STACKSAVE and STACKRESTORE

[kaz7]

Summary

Change to use default expanded code. Add regression tests also.

[simoll]

llvm/test/CodeGen/VE/Scalar/stacksave.ll

18–19

Why do we want %s11 to be assigned twice?

[kaz7]

Thank you for comment.

llvm/test/CodeGen/VE/Scalar/stacksave.ll

18–19

stackrestore assignes %s0 to %s11 (=%sp). Then, epilogue of this function restore %s11 again using %s9 (=%fp=saved stack pointer).

[simoll]

Thx!

llvm/lib/Target/VE/VEISelLowering.cpp

void VETargetLowering::initSPUActions() {
   // Use the default implementation.
   setOperationAction(ISD::VACOPY, MVT::Other, Expand);
   setOperationAction(ISD::VAEND, MVT::Other, Expand);
   /// } VAARG handling
 
   /// Stack {
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64, Custom);
+
+  // Use the default implementation.
+  setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
+  setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
   /// } Stack
 
   /// Branch {
 
   // VE doesn't have BRCOND
   setOperationAction(ISD::BRCOND, MVT::Other, Expand);
 
   // BR_JT is not implemented yet.

llvm/test/CodeGen/VE/Scalar/stacksave.ll

+; RUN: llc < %s -mtriple=ve | FileCheck %s
+
+; Function Attrs: noinline nounwind optnone
+define i8* @stacksave() {
+; CHECK-LABEL: stacksave:
+; CHECK:       .LBB{{[0-9]+}}_2:
+; CHECK-NEXT:    or %s0, 0, %s11
+; CHECK-NEXT:    or %s11, 0, %s9
+  %ret = call i8* @llvm.stacksave()
+  ret i8* %ret
+}
+
+; Function Attrs: noinline nounwind optnone
+define void @stackrestore(i8* %ptr) {
+; CHECK-LABEL: stackrestore:
+; CHECK:       .LBB{{[0-9]+}}_2:
+; CHECK-NEXT:    or %s11, 0, %s0
+; CHECK-NEXT:    or %s11, 0, %s9
+  call void @llvm.stackrestore(i8* %ptr)
+  ret void
+}
+
+; Function Attrs: nounwind
+declare i8* @llvm.stacksave()
+; Function Attrs: nounwind
+declare void @llvm.stackrestore(i8*)