[PATCH] D110834: [PHIElimination] Account for INLINEASM_BR when inserting kills

[Jay Foad via Phabricator via llvm-commits]

foad updated this revision to Diff 377786.
foad added a comment.

Switch to a MIR test case.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110834/new/

https://reviews.llvm.org/D110834

Files:
  llvm/lib/CodeGen/PHIElimination.cpp
  llvm/test/CodeGen/X86/callbr-asm-kill.mir


Index: llvm/test/CodeGen/X86/callbr-asm-kill.mir
===================================================================
--- llvm/test/CodeGen/X86/callbr-asm-kill.mir
+++ llvm/test/CodeGen/X86/callbr-asm-kill.mir
@@ -1,8 +1,9 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 # RUN: llc -mtriple=x86_64-unknown-linux-gnu -verify-machineinstrs -O2 -run-pass=livevars,phi-node-elimination -o - %s | FileCheck %s
 
-# FIXME: The COPY from [[MOV64rm]] should not be killed, because there is a
-# subsequent use of [[MOV64rm]] in the INLINEASM_BR instruction.
+# Check that the COPY from [[MOV64rm]] is not killed, because there is a
+# subsequent use of [[MOV64rm]] in the INLINEASM_BR instruction which should be
+# killed instead.
 --- |
   ; ModuleID = '<stdin>'
   source_filename = "<stdin>"
@@ -65,8 +66,8 @@
   ; CHECK-NEXT:   $rdi = COPY killed [[COPY3]]
   ; CHECK-NEXT:   CALL64pcrel32 target-flags(x86-plt) @foo, csr_64, implicit $rsp, implicit $ssp, implicit killed $rdi, implicit-def $rsp, implicit-def $ssp
   ; CHECK-NEXT:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
-  ; CHECK-NEXT:   [[COPY4:%[0-9]+]]:gr64 = COPY killed [[MOV64rm]]
-  ; CHECK-NEXT:   INLINEASM_BR &"", 9 /* sideeffect mayload attdialect */, 196654 /* mem:m */, [[MOV64rm]], 1, $noreg, 0, $noreg, 13 /* imm */, blockaddress(@test1, %ir-block.loop)
+  ; CHECK-NEXT:   [[COPY4:%[0-9]+]]:gr64 = COPY [[MOV64rm]]
+  ; CHECK-NEXT:   INLINEASM_BR &"", 9 /* sideeffect mayload attdialect */, 196654 /* mem:m */, killed [[MOV64rm]], 1, $noreg, 0, $noreg, 13 /* imm */, blockaddress(@test1, %ir-block.loop)
   ; CHECK-NEXT:   JMP_1 %bb.2
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.2.end:
Index: llvm/lib/CodeGen/PHIElimination.cpp
===================================================================
--- llvm/lib/CodeGen/PHIElimination.cpp
+++ llvm/lib/CodeGen/PHIElimination.cpp
@@ -524,9 +524,8 @@
       // case, we should mark the last such terminator as being the killing
       // block, not the copy.
       MachineBasicBlock::iterator KillInst = opBlock.end();
-      MachineBasicBlock::iterator FirstTerm = opBlock.getFirstTerminator();
-      for (MachineBasicBlock::iterator Term = FirstTerm;
-          Term != opBlock.end(); ++Term) {
+      for (MachineBasicBlock::iterator Term = InsertPos; Term != opBlock.end();
+           ++Term) {
         if (Term->readsRegister(SrcReg))
           KillInst = Term;
       }
@@ -536,7 +535,7 @@
 
         if (reusedIncoming || !IncomingReg) {
           // We may have to rewind a bit if we didn't insert a copy this time.
-          KillInst = FirstTerm;
+          KillInst = InsertPos;
           while (KillInst != opBlock.begin()) {
             --KillInst;
             if (KillInst->isDebugInstr())
@@ -583,9 +582,8 @@
 
         if (!isLiveOut) {
           MachineBasicBlock::iterator KillInst = opBlock.end();
-          MachineBasicBlock::iterator FirstTerm = opBlock.getFirstTerminator();
-          for (MachineBasicBlock::iterator Term = FirstTerm;
-              Term != opBlock.end(); ++Term) {
+          for (MachineBasicBlock::iterator Term = InsertPos;
+               Term != opBlock.end(); ++Term) {
             if (Term->readsRegister(SrcReg))
               KillInst = Term;
           }
@@ -595,7 +593,7 @@
 
             if (reusedIncoming || !IncomingReg) {
               // We may have to rewind a bit if we didn't just insert a copy.
-              KillInst = FirstTerm;
+              KillInst = InsertPos;
               while (KillInst != opBlock.begin()) {
                 --KillInst;
                 if (KillInst->isDebugInstr())


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