From b38a51e92cbdf37010a07a461d004c25cdc033f5 Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Mon, 20 Mar 2017 21:58:23 +0000
Subject: [PATCH] GlobalISel: add implicit defs & uses when mutating an
 instruction.

Otherwise a scheduler might do bad things to the code we produce.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298311 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/AArch64/GlobalISel/select-binop.mir |  4 ++--
 utils/TableGen/GlobalISelEmitter.cpp             | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/test/CodeGen/AArch64/GlobalISel/select-binop.mir b/test/CodeGen/AArch64/GlobalISel/select-binop.mir
index a15b56fe2d6..8ae2e1b2eb7 100644
--- a/test/CodeGen/AArch64/GlobalISel/select-binop.mir
+++ b/test/CodeGen/AArch64/GlobalISel/select-binop.mir
@@ -224,7 +224,7 @@ registers:
 # CHECK:  body:
 # CHECK:    %0 = COPY %w0
 # CHECK:    %1 = COPY %w1
-# CHECK:    %2 = SUBSWrr %0, %1
+# CHECK:    %2 = SUBSWrr %0, %1, implicit-def %nzcv
 body:             |
   bb.0:
     liveins: %w0, %w1
@@ -254,7 +254,7 @@ registers:
 # CHECK:  body:
 # CHECK:    %0 = COPY %x0
 # CHECK:    %1 = COPY %x1
-# CHECK:    %2 = SUBSXrr %0, %1
+# CHECK:    %2 = SUBSXrr %0, %1, implicit-def %nzcv
 body:             |
   bb.0:
     liveins: %x0, %x1
diff --git a/utils/TableGen/GlobalISelEmitter.cpp b/utils/TableGen/GlobalISelEmitter.cpp
index 596cd3cddb9..169dd32daa6 100644
--- a/utils/TableGen/GlobalISelEmitter.cpp
+++ b/utils/TableGen/GlobalISelEmitter.cpp
@@ -835,8 +835,25 @@ public:
   void emitCxxActionStmts(raw_ostream &OS, RuleMatcher &Rule,
                           StringRef RecycleVarName) const override {
     if (canMutate()) {
-      OS << RecycleVarName << ".setDesc(TII.get(" << I->Namespace
+      OS << "    " << RecycleVarName << ".setDesc(TII.get(" << I->Namespace
          << "::" << I->TheDef->getName() << "));\n";
+
+      if (!I->ImplicitDefs.empty() || !I->ImplicitUses.empty()) {
+        OS << "    auto MIB = MachineInstrBuilder(MF, &" << RecycleVarName
+           << ");\n";
+
+        for (auto Def : I->ImplicitDefs) {
+          auto Namespace = Def->getValueAsString("Namespace");
+          OS << "    MIB.addDef(" << Namespace << "::" << Def->getName()
+             << ", RegState::Implicit);\n";
+        }
+        for (auto Use : I->ImplicitUses) {
+          auto Namespace = Use->getValueAsString("Namespace");
+          OS << "    MIB.addUse(" << Namespace << "::" << Use->getName()
+             << ", RegState::Implicit);\n";
+        }
+      }
+
       OS << "    MachineInstr &NewI = " << RecycleVarName << ";\n";
       return;
     }
-- 
2.11.0