From b328d95333e08cbcd70ead2ebbfd00cfc97000df Mon Sep 17 00:00:00 2001
From: Jessica Paquette <jpaquette@apple.com>
Date: Fri, 5 Oct 2018 21:02:46 +0000
Subject: [PATCH] [GlobalIsel] Add llvm.invariant.start and llvm.invariant.end

Port over the implementation in SelectionDAGBuilder.cpp into the IRTranslator
and update the arm64-irtranslator test.

These were causing fallbacks in CTMark/Bullet (-Rpass-missed=gisel-select),
and this patch fixes that.

https://reviews.llvm.org/D52945

llvm-svn: 343885
---
 llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp               |  8 ++++++++
 llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index ff1ad71..709965b 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -955,6 +955,14 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
         .addUse(getOrCreateVReg(*CI.getArgOperand(0)));
     return true;
   }
+  case Intrinsic::invariant_start: {
+    LLT PtrTy = getLLTForType(*CI.getArgOperand(0)->getType(), *DL);
+    unsigned Undef = MRI->createGenericVirtualRegister(PtrTy);
+    MIRBuilder.buildUndef(Undef);
+    return true;
+  }
+  case Intrinsic::invariant_end:
+    return true;
   }
   return false;
 }
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
index a2bbc27..a021eed 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -2207,3 +2207,17 @@ define void @test_blockaddress() {
 block:
   ret void
 }
+
+%t = type { i32 }
+declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture) readonly nounwind
+declare void @llvm.invariant.end.p0i8({}*, i64, i8* nocapture) nounwind
+define void @test_invariant_intrin() {
+; CHECK-LABEL: name: test_invariant_intrin
+; CHECK: %{{[0-9]+}}:_(s64) = G_IMPLICIT_DEF
+; CHECK-NEXT: RET_ReallyLR
+  %x = alloca %t
+  %y = bitcast %t* %x to i8*
+  %inv = call {}* @llvm.invariant.start.p0i8(i64 8, i8* %y)
+  call void @llvm.invariant.end.p0i8({}* %inv, i64 8, i8* %y)
+  ret void
+}
-- 
2.7.4