From c5df1fd8db52905a5af2cb02716e4d3300ef2a72 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Thu, 31 Oct 2024 14:48:31 +0100
Subject: [PATCH 1/6] Allow KILL MI with dangling MMO in MachineVerifier.

---
 llvm/lib/CodeGen/MachineVerifier.cpp          |  2 +-
 .../CodeGen/SystemZ/machine-ver-kill-memop.ll | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll

diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index e2c09fe25d55c..cc5acccdc8df6 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2271,7 +2271,7 @@ void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) {
 
   // Check the MachineMemOperands for basic consistency.
   for (MachineMemOperand *Op : MI->memoperands()) {
-    if (Op->isLoad() && !MI->mayLoad())
+    if (Op->isLoad() && (!MI->mayLoad() && !MI->isKill()))
       report("Missing mayLoad flag", MI);
     if (Op->isStore() && !MI->mayStore())
       report("Missing mayStore flag", MI);
diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
new file mode 100644
index 0000000000000..b3cbc332f473a
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z16 -disable-machine-dce \
+; RUN:   -verify-machineinstrs -O3
+;
+; Test that this passes the verifier even though a KILL instruction with a
+; dangling memory operand emerges.
+
+define void @fun(ptr %Src, ptr %Dst) {
+  br label %2
+
+2:
+  %3 = load i32, ptr %Src, align 4
+  %4 = freeze i32 %3
+  %5 = icmp eq i32 %4, 0
+  %6 = load i32, ptr poison, align 4
+  %7 = select i1 %5, i32 0, i32 %6
+  %8 = load i32, ptr %Src, align 4
+  %9 = freeze i32 %8
+  %10 = icmp eq i32 %9, 0
+  %11 = load i32, ptr poison, align 4
+  %12 = select i1 %10, i32 0, i32 %11
+  br label %13
+
+13:
+  %14 = phi i32 [ %12, %13 ], [ %7, %2 ]
+  %15 = icmp slt i32 %14, 5
+  %16 = zext i1 %15 to i64
+  %17 = xor i64 poison, %16
+  store i64 %17, ptr %Dst, align 8
+  br label %13
+}

From f03ba98cae95ae64800ffc8d4d1de555375504b3 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Mon, 4 Nov 2024 15:19:42 -0600
Subject: [PATCH 2/6] Remove the MMO instead in LiveRangeEdit.

---
 llvm/lib/CodeGen/LiveRangeEdit.cpp                  | 1 +
 llvm/lib/CodeGen/MachineVerifier.cpp                | 2 +-
 llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll | 4 ++--
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/CodeGen/LiveRangeEdit.cpp b/llvm/lib/CodeGen/LiveRangeEdit.cpp
index c3c581d42236e..7b630e88b2a60 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.cpp
+++ b/llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -385,6 +385,7 @@ void LiveRangeEdit::eliminateDeadDef(MachineInstr *MI, ToShrinkSet &ToShrink) {
         continue;
       MI->removeOperand(i-1);
     }
+    MI->dropMemRefs(*MI->getMF());
     LLVM_DEBUG(dbgs() << "Converted physregs to:\t" << *MI);
   } else {
     // If the dest of MI is an original reg and MI is reMaterializable,
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index cc5acccdc8df6..e2c09fe25d55c 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2271,7 +2271,7 @@ void MachineVerifier::visitMachineInstrBefore(const MachineInstr *MI) {
 
   // Check the MachineMemOperands for basic consistency.
   for (MachineMemOperand *Op : MI->memoperands()) {
-    if (Op->isLoad() && (!MI->mayLoad() && !MI->isKill()))
+    if (Op->isLoad() && !MI->mayLoad())
       report("Missing mayLoad flag", MI);
     if (Op->isStore() && !MI->mayStore())
       report("Missing mayStore flag", MI);
diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
index b3cbc332f473a..793fd3908b9f8 100644
--- a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
+++ b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
@@ -1,8 +1,8 @@
 ; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z16 -disable-machine-dce \
 ; RUN:   -verify-machineinstrs -O3
 ;
-; Test that this passes the verifier even though a KILL instruction with a
-; dangling memory operand emerges.
+; Test that the MemoryOperand of the produced KILL instruction is removed
+; and as a result the machine verifier succeeds.
 
 define void @fun(ptr %Src, ptr %Dst) {
   br label %2

From 772910b77b2195829a6827e2d32807f1b996ff98 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Mon, 4 Nov 2024 15:40:49 -0600
Subject: [PATCH 3/6] Make a simpler .mir test.

---
 .../CodeGen/SystemZ/machine-ver-kill-memop.ll | 30 -----------
 .../SystemZ/machine-ver-kill-memop.mir        | 52 +++++++++++++++++++
 2 files changed, 52 insertions(+), 30 deletions(-)
 delete mode 100644 llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
 create mode 100644 llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir

diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
deleted file mode 100644
index 793fd3908b9f8..0000000000000
--- a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.ll
+++ /dev/null
@@ -1,30 +0,0 @@
-; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z16 -disable-machine-dce \
-; RUN:   -verify-machineinstrs -O3
-;
-; Test that the MemoryOperand of the produced KILL instruction is removed
-; and as a result the machine verifier succeeds.
-
-define void @fun(ptr %Src, ptr %Dst) {
-  br label %2
-
-2:
-  %3 = load i32, ptr %Src, align 4
-  %4 = freeze i32 %3
-  %5 = icmp eq i32 %4, 0
-  %6 = load i32, ptr poison, align 4
-  %7 = select i1 %5, i32 0, i32 %6
-  %8 = load i32, ptr %Src, align 4
-  %9 = freeze i32 %8
-  %10 = icmp eq i32 %9, 0
-  %11 = load i32, ptr poison, align 4
-  %12 = select i1 %10, i32 0, i32 %11
-  br label %13
-
-13:
-  %14 = phi i32 [ %12, %13 ], [ %7, %2 ]
-  %15 = icmp slt i32 %14, 5
-  %16 = zext i1 %15 to i64
-  %17 = xor i64 poison, %16
-  store i64 %17, ptr %Dst, align 8
-  br label %13
-}
diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
new file mode 100644
index 0000000000000..d4eb7ff1a7040
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
@@ -0,0 +1,52 @@
+# RUN: llc -o /dev/null %s -mtriple=s390x-linux-gnu -mcpu=z16 \
+# RUN:   -disable-machine-dce -verify-machineinstrs -run-pass=register-coalescer
+
+# Test that the MemoryOperand of the produced KILL instruction is removed
+# and as a result the machine verifier succeeds.
+
+--- |
+  define void @fun(ptr %Src, ptr %Dst, ptr %Src2) {
+    ret void
+  }
+...
+---
+name:            fun
+alignment:       16
+tracksRegLiveness: true
+noPhis:          true
+isSSA:           false
+noVRegs:         false
+hasFakeUses:     false
+registers:
+  - { id: 0, class: grx32bit }
+  - { id: 1, class: grx32bit }
+  - { id: 2, class: grx32bit }
+  - { id: 3, class: addr64bit }
+  - { id: 4, class: gr64bit }
+  - { id: 5, class: grx32bit }
+  - { id: 6, class: grx32bit }
+  - { id: 7, class: grx32bit }
+  - { id: 8, class: addr64bit }
+liveins:
+  - { reg: '$r2d', virtual-reg: '%3' }
+frameInfo:
+  maxAlignment:    1
+machineFunctionInfo: {}
+body:             |
+  bb.0:
+    liveins: $r2d
+  
+    %3:addr64bit = COPY killed $r2d
+  
+  bb.1:
+    %5:grx32bit = LMux killed %3, 0, $noreg :: (load (s32) from %ir.Src)
+    CHIMux killed %5, 0, implicit-def $cc
+    %7:grx32bit = LHIMux 0
+    %1:grx32bit = COPY killed %7
+    %1:grx32bit = LOCMux %1, undef %8:addr64bit, 0, 14, 6, implicit killed $cc :: (load (s32) from %ir.Src2)
+    dead %0:grx32bit = COPY killed %1
+  
+  bb.2:
+    J %bb.2
+
+...

From f71dc9329840444e2feaf482f79289a91de12a4f Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Mon, 4 Nov 2024 15:47:52 -0600
Subject: [PATCH 4/6] Remove stray llc option in test.

---
 llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
index d4eb7ff1a7040..71751a9e245c3 100644
--- a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
+++ b/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
@@ -1,5 +1,5 @@
 # RUN: llc -o /dev/null %s -mtriple=s390x-linux-gnu -mcpu=z16 \
-# RUN:   -disable-machine-dce -verify-machineinstrs -run-pass=register-coalescer
+# RUN:   -verify-machineinstrs -run-pass=register-coalescer
 
 # Test that the MemoryOperand of the produced KILL instruction is removed
 # and as a result the machine verifier succeeds.

From 1ee2226b617119c723f491d40824160be2505212 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Mon, 4 Nov 2024 16:33:55 -0600
Subject: [PATCH 5/6] Updates to .mir test per review.

---
 ...chine-ver-kill-memop.mir => kill-remove-memop.mir} | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)
 rename llvm/test/CodeGen/SystemZ/{machine-ver-kill-memop.mir => kill-remove-memop.mir} (81%)

diff --git a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir b/llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
similarity index 81%
rename from llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
rename to llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
index 71751a9e245c3..c432dc1cabbcf 100644
--- a/llvm/test/CodeGen/SystemZ/machine-ver-kill-memop.mir
+++ b/llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
@@ -2,13 +2,8 @@
 # RUN:   -verify-machineinstrs -run-pass=register-coalescer
 
 # Test that the MemoryOperand of the produced KILL instruction is removed
-# and as a result the machine verifier succeeds.
+# (and as a result the machine verifier succeeds).
 
---- |
-  define void @fun(ptr %Src, ptr %Dst, ptr %Src2) {
-    ret void
-  }
-...
 ---
 name:            fun
 alignment:       16
@@ -39,11 +34,11 @@ body:             |
     %3:addr64bit = COPY killed $r2d
   
   bb.1:
-    %5:grx32bit = LMux killed %3, 0, $noreg :: (load (s32) from %ir.Src)
+    %5:grx32bit = LMux killed %3, 0, $noreg :: (load (s32))
     CHIMux killed %5, 0, implicit-def $cc
     %7:grx32bit = LHIMux 0
     %1:grx32bit = COPY killed %7
-    %1:grx32bit = LOCMux %1, undef %8:addr64bit, 0, 14, 6, implicit killed $cc :: (load (s32) from %ir.Src2)
+    %1:grx32bit = LOCMux %1, undef %8:addr64bit, 0, 14, 6, implicit killed $cc :: (load (s32))
     dead %0:grx32bit = COPY killed %1
   
   bb.2:

From 48ecf405b0ca2d6580acd7526f7d242840d26031 Mon Sep 17 00:00:00 2001
From: Jonas Paulsson <paulson1@linux.ibm.com>
Date: Mon, 4 Nov 2024 21:25:24 -0600
Subject: [PATCH 6/6] Test updated again.

---
 .../CodeGen/SystemZ/kill-remove-memop.mir     | 47 -------------------
 .../SystemZ/liverangeedit-kill-memop.mir      | 29 ++++++++++++
 2 files changed, 29 insertions(+), 47 deletions(-)
 delete mode 100644 llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
 create mode 100644 llvm/test/CodeGen/SystemZ/liverangeedit-kill-memop.mir

diff --git a/llvm/test/CodeGen/SystemZ/kill-remove-memop.mir b/llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
deleted file mode 100644
index c432dc1cabbcf..0000000000000
--- a/llvm/test/CodeGen/SystemZ/kill-remove-memop.mir
+++ /dev/null
@@ -1,47 +0,0 @@
-# RUN: llc -o /dev/null %s -mtriple=s390x-linux-gnu -mcpu=z16 \
-# RUN:   -verify-machineinstrs -run-pass=register-coalescer
-
-# Test that the MemoryOperand of the produced KILL instruction is removed
-# (and as a result the machine verifier succeeds).
-
----
-name:            fun
-alignment:       16
-tracksRegLiveness: true
-noPhis:          true
-isSSA:           false
-noVRegs:         false
-hasFakeUses:     false
-registers:
-  - { id: 0, class: grx32bit }
-  - { id: 1, class: grx32bit }
-  - { id: 2, class: grx32bit }
-  - { id: 3, class: addr64bit }
-  - { id: 4, class: gr64bit }
-  - { id: 5, class: grx32bit }
-  - { id: 6, class: grx32bit }
-  - { id: 7, class: grx32bit }
-  - { id: 8, class: addr64bit }
-liveins:
-  - { reg: '$r2d', virtual-reg: '%3' }
-frameInfo:
-  maxAlignment:    1
-machineFunctionInfo: {}
-body:             |
-  bb.0:
-    liveins: $r2d
-  
-    %3:addr64bit = COPY killed $r2d
-  
-  bb.1:
-    %5:grx32bit = LMux killed %3, 0, $noreg :: (load (s32))
-    CHIMux killed %5, 0, implicit-def $cc
-    %7:grx32bit = LHIMux 0
-    %1:grx32bit = COPY killed %7
-    %1:grx32bit = LOCMux %1, undef %8:addr64bit, 0, 14, 6, implicit killed $cc :: (load (s32))
-    dead %0:grx32bit = COPY killed %1
-  
-  bb.2:
-    J %bb.2
-
-...
diff --git a/llvm/test/CodeGen/SystemZ/liverangeedit-kill-memop.mir b/llvm/test/CodeGen/SystemZ/liverangeedit-kill-memop.mir
new file mode 100644
index 0000000000000..8cfa22d2469e2
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/liverangeedit-kill-memop.mir
@@ -0,0 +1,29 @@
+# RUN: llc -o /dev/null %s -mtriple=s390x-linux-gnu -mcpu=z16 \
+# RUN:   -verify-machineinstrs -run-pass=register-coalescer
+
+# The LOCMux below produces a dead definition and will be turned into
+# a KILL instruction (by LiveRangeEdit::eliminateDeadDef()). When this
+# happens, the MemoryOperand must also be removed as this is required
+# by the machine verifier.
+
+---
+name:            fun
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $r2d
+  
+    %3:addr64bit = COPY killed $r2d
+  
+  bb.1:
+    %5:grx32bit = LMux killed %3, 0, $noreg :: (load (s32))
+    CHIMux killed %5, 0, implicit-def $cc
+    %7:grx32bit = LHIMux 0
+    %1:grx32bit = COPY killed %7
+    %1:grx32bit = LOCMux %1, undef %8:addr64bit, 0, 14, 6, implicit killed $cc :: (load (s32))
+    dead %0:grx32bit = COPY killed %1
+  
+  bb.2:
+    J %bb.2
+
+...