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

[Jay Foad via Phabricator via llvm-commits]

foad updated this revision to Diff 376588.
foad added a comment.

Rebase on a test case that I will pre-commit.


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.ll


Index: llvm/test/CodeGen/X86/callbr-asm-kill.ll
===================================================================
--- llvm/test/CodeGen/X86/callbr-asm-kill.ll
+++ llvm/test/CodeGen/X86/callbr-asm-kill.ll
@@ -3,8 +3,9 @@
 
 declare void @foo(i8*)
 
-; 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.
 define void @test1(i8* %arg, i8** %mem) nounwind {
   ; CHECK-LABEL: name: test1
   ; CHECK: bb.0.entry:
@@ -24,8 +25,8 @@
   ; 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
@@ -515,9 +515,8 @@
       // 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;
       }
@@ -527,7 +526,7 @@
 
         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())
@@ -574,9 +573,8 @@
 
         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;
           }
@@ -586,7 +584,7 @@
 
             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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