[llvm] Improvements to RS4GC BDV Algorithm (PR #69795)

[via llvm-commits]

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@@ -0,0 +1,56 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt < %s -passes=rewrite-statepoints-for-gc -S 2>&1 | FileCheck %s
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @barney() gc "statepoint-example" {
+; CHECK-LABEL: define void @barney() gc "statepoint-example" {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[GETELEMENTPTR:%.*]] = getelementptr i8, <2 x ptr addrspace(1)> zeroinitializer, <2 x i64> <i64 16, i64 8>
+; CHECK-NEXT:    [[EXTRACTELEMENT_BASE:%.*]] = extractelement <2 x ptr addrspace(1)> zeroinitializer, i32 0, !is_base_value !0
+; CHECK-NEXT:    [[EXTRACTELEMENT:%.*]] = extractelement <2 x ptr addrspace(1)> [[GETELEMENTPTR]], i32 0
+; CHECK-NEXT:    [[INSERTELEMENT_BASE:%.*]] = insertelement <2 x ptr addrspace(1)> zeroinitializer, ptr addrspace(1) [[EXTRACTELEMENT_BASE]], i32 0, !is_base_value !0
+; CHECK-NEXT:    [[INSERTELEMENT:%.*]] = insertelement <2 x ptr addrspace(1)> zeroinitializer, ptr addrspace(1) [[EXTRACTELEMENT]], i32 0
+; CHECK-NEXT:    [[STATEPOINT_TOKEN:%.*]] = call token (i64, i32, ptr, i32, i32, ...) @llvm.experimental.gc.statepoint.p0(i64 2882400000, i32 0, ptr elementtype(i8 ()) @foo, i32 0, i32 0, i32 0, i32 0) [ "gc-live"(<2 x ptr addrspace(1)> [[INSERTELEMENT]], <2 x ptr addrspace(1)> [[INSERTELEMENT_BASE]]) ]
+; CHECK-NEXT:    [[INSERTELEMENT_RELOCATED:%.*]] = call coldcc <2 x ptr addrspace(1)> @llvm.experimental.gc.relocate.v2p1(token [[STATEPOINT_TOKEN]], i32 1, i32 0)
+; CHECK-NEXT:    [[INSERTELEMENT_BASE_RELOCATED:%.*]] = call coldcc <2 x ptr addrspace(1)> @llvm.experimental.gc.relocate.v2p1(token [[STATEPOINT_TOKEN]], i32 1, i32 1)
+; CHECK-NEXT:    [[EXTRACTELEMENT1:%.*]] = extractelement <2 x ptr addrspace(1)> [[INSERTELEMENT_RELOCATED]], i32 0
+; CHECK-NEXT:    ret void
+;
+bb:
+  %getelementptr = getelementptr i8, <2 x ptr addrspace(1)> zeroinitializer, <2 x i64> <i64 16, i64 8>
+  %extractelement = extractelement <2 x ptr addrspace(1)> %getelementptr, i32 0
+  %insertelement = insertelement <2 x ptr addrspace(1)> zeroinitializer, ptr addrspace(1) %extractelement, i32 0
+  %call = call i8 @foo()
+  %extractelement1 = extractelement <2 x ptr addrspace(1)> %insertelement, i32 0
+  ret void
+}
+
+
+define void @bart() gc "statepoint-example" {
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annamthomas wrote:

Pls add a comment here that this is same as above, but shows transitive uses of insertelement.

https://github.com/llvm/llvm-project/pull/69795