[RS4GC] Handle freeze case for vector

[skatkov]

Summary

Finding BDV for vector value does not handle freeze instruction.
Adding its handling as it is done for scalar case.

[apilipenko]

In other instructions, we seem to just duplicate the handling in findBaseDefiningValueOfVector and findBaseDefiningValue. Doing so for freeze would be more consistent with the existing code.

LGTM.

[skatkov]

Update pat h before landing to handle reviewer's comment.

llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

static Value *findBaseDefiningValueOfVector(Value *I, DefiningValueMapTy &Cache,
   // non-vector data types.
   if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
     auto *BDV =
         findBaseDefiningValue(GEP->getPointerOperand(), Cache, KnownBases);
     Cache[GEP] = BDV;
     return BDV;
   }
 
+  // The behavior of freeze instructions is the same for vector and
+  // non-vector data types.
+  if (auto *Freeze = dyn_cast<FreezeInst>(I)) {
+    auto *BDV = findBaseDefiningValue(Freeze->getOperand(0), Cache, KnownBases);
+    Cache[Freeze] = BDV;
+    return BDV;
+  }
+
   // If the pointer comes through a bitcast of a vector of pointers to
   // a vector of another type of pointer, then look through the bitcast
   if (auto *BC = dyn_cast<BitCastInst>(I)) {
     auto *BDV = findBaseDefiningValue(BC->getOperand(0), Cache, KnownBases);
     Cache[BC] = BDV;
     return BDV;
   }
 

llvm/test/Transforms/RewriteStatepointsForGC/freeze.ll

+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=rewrite-statepoints-for-gc < %s | FileCheck %s
+
+declare void @hoge()
+
+define i8 addrspace(1)* @testVector(<3 x i8 addrspace(1)*> %arg) gc "statepoint-example" {
+; CHECK-LABEL: @testVector(
+; CHECK-NEXT:    [[A:%.*]] = freeze <3 x i8 addrspace(1)*> [[ARG:%.*]]
+; CHECK-NEXT:    [[BASE_EE:%.*]] = extractelement <3 x i8 addrspace(1)*> [[ARG]], i64 2, !is_base_value !0
+; CHECK-NEXT:    [[B:%.*]] = extractelement <3 x i8 addrspace(1)*> [[A]], i64 2
+; CHECK-NEXT:    [[STATEPOINT_TOKEN:%.*]] = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* elementtype(void ()) @hoge, i32 0, i32 0, i32 0, i32 0) [ "deopt"(), "gc-live"(i8 addrspace(1)* [[B]], i8 addrspace(1)* [[BASE_EE]]) ]
+; CHECK-NEXT:    [[B_RELOCATED:%.*]] = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token [[STATEPOINT_TOKEN]], i32 1, i32 0)
+; CHECK-NEXT:    [[BASE_EE_RELOCATED:%.*]] = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token [[STATEPOINT_TOKEN]], i32 1, i32 1)
+; CHECK-NEXT:    ret i8 addrspace(1)* [[B_RELOCATED]]
+;
+  %a = freeze <3 x i8 addrspace(1)*> %arg
+  %b = extractelement <3 x i8 addrspace(1)*> %a, i64 2
+  call void @hoge() ["deopt"()]
+  ret i8 addrspace(1)* %b
+}
+
+define i8 addrspace(1)* @testScalar(i8 addrspace(1)* %arg) gc "statepoint-example" {
+; CHECK-LABEL: @testScalar(
+; CHECK-NEXT:    [[A:%.*]] = freeze i8 addrspace(1)* [[ARG:%.*]]
+; CHECK-NEXT:    [[STATEPOINT_TOKEN:%.*]] = call token (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 2882400000, i32 0, void ()* elementtype(void ()) @hoge, i32 0, i32 0, i32 0, i32 0) [ "deopt"(), "gc-live"(i8 addrspace(1)* [[A]], i8 addrspace(1)* [[ARG]]) ]
+; CHECK-NEXT:    [[A_RELOCATED:%.*]] = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token [[STATEPOINT_TOKEN]], i32 1, i32 0)
+; CHECK-NEXT:    [[ARG_RELOCATED:%.*]] = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(token [[STATEPOINT_TOKEN]], i32 1, i32 1)
+; CHECK-NEXT:    ret i8 addrspace(1)* [[A_RELOCATED]]
+;
+  %a = freeze i8 addrspace(1)* %arg
+  call void @hoge() ["deopt"()]
+  ret i8 addrspace(1)* %a
+}
+