[CodeGen] Fix nomerge attribute not working in tail calls.

In D79537, `nomerge` was made to only apply to non-tail calls. This fixes it by also applying it to tail calls. For ARM, I only made the new MI to inherit the flag under `TCRETURNdi` and `TCRETURNri`, because that's the place tail calls got replaced. Not sure if there's any other place needed. Fixes #61545. Reviewed By: rnk Differential Revision: https://reviews.llvm.org/D146749
llvm · May 10, 2023 · 3977b77 · 3977b77
1 parent 2ec334d
commit 3977b77
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Showing 14 changed files with 40 additions and 5 deletions.
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -7599,6 +7599,7 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
     if (IsCFICall)
       Ret.getNode()->setCFIType(CLI.CFIType->getZExtValue());
 
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
     DAG.addCallSiteInfo(Ret.getNode(), std::move(CSInfo));
     return Ret;
   }

diff --git a/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp b/llvm/lib/Target/ARM/ARMExpandPseudoInsts.cpp
@@ -2171,6 +2171,9 @@ bool ARMExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
       // Update call site info and delete the pseudo instruction TCRETURN.
       if (MI.isCandidateForCallSiteEntry())
         MI.getMF()->moveCallSiteInfo(&MI, &*NewMI);
+      // Copy nomerge flag over to new instruction.
+      if (MI.getFlag(MachineInstr::NoMerge))
+        NewMI->setFlag(MachineInstr::NoMerge);
       MBB.erase(MBBI);
 
       MBBI = NewMI;

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -2857,6 +2857,7 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   if (isTailCall) {
     MF.getFrameInfo().setHasTailCall();
     SDValue Ret = DAG.getNode(ARMISD::TC_RETURN, dl, NodeTys, Ops);
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
     DAG.addCallSiteInfo(Ret.getNode(), std::move(CSInfo));
     return Ret;
   }

diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -2638,7 +2638,9 @@ LoongArchTargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   if (IsTailCall) {
     MF.getFrameInfo().setHasTailCall();
-    return DAG.getNode(LoongArchISD::TAIL, DL, NodeTys, Ops);
+    SDValue Ret = DAG.getNode(LoongArchISD::TAIL, DL, NodeTys, Ops);
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
+    return Ret;
   }
 
   Chain = DAG.getNode(LoongArchISD::CALL, DL, NodeTys, Ops);

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -5629,7 +5629,9 @@ SDValue PPCTargetLowering::FinishCall(
     assert(CallOpc == PPCISD::TC_RETURN &&
            "Unexpected call opcode for a tail call.");
     DAG.getMachineFunction().getFrameInfo().setHasTailCall();
-    return DAG.getNode(CallOpc, dl, MVT::Other, Ops);
+    SDValue Ret = DAG.getNode(CallOpc, dl, MVT::Other, Ops);
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CFlags.NoMerge);
+    return Ret;
   }
 
   std::array<EVT, 2> ReturnTypes = {{MVT::Other, MVT::Glue}};

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -14671,7 +14671,9 @@ SDValue RISCVTargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   if (IsTailCall) {
     MF.getFrameInfo().setHasTailCall();
-    return DAG.getNode(RISCVISD::TAIL, DL, NodeTys, Ops);
+    SDValue Ret = DAG.getNode(RISCVISD::TAIL, DL, NodeTys, Ops);
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
+    return Ret;
   }
 
   Chain = DAG.getNode(RISCVISD::CALL, DL, NodeTys, Ops);

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1849,8 +1849,11 @@ SystemZTargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   // Emit the call.
   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
-  if (IsTailCall)
-    return DAG.getNode(SystemZISD::SIBCALL, DL, NodeTys, Ops);
+  if (IsTailCall) {
+    SDValue Ret = DAG.getNode(SystemZISD::SIBCALL, DL, NodeTys, Ops);
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
+    return Ret;
+  }
   Chain = DAG.getNode(SystemZISD::CALL, DL, NodeTys, Ops);
   DAG.addNoMergeSiteInfo(Chain.getNode(), CLI.NoMerge);
   Glue = Chain.getValue(1);

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -4984,6 +4984,7 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     if (IsCFICall)
       Ret.getNode()->setCFIType(CLI.CFIType->getZExtValue());
 
+    DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
     DAG.addCallSiteInfo(Ret.getNode(), std::move(CSInfo));
     return Ret;
   }

diff --git a/llvm/test/CodeGen/AArch64/nomerge.ll b/llvm/test/CodeGen/AArch64/nomerge.ll
@@ -41,6 +41,10 @@ if.end3:
 define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    tbz w0, #0, .LBB1_2
+; CHECK-NEXT:  // %bb.1: // %if.then
+; CHECK-NEXT:    b bar
+; CHECK-NEXT:  .LBB1_2: // %if.else
 ; CHECK-NEXT:    b bar
 entry:
   br i1 %i, label %if.then, label %if.else

diff --git a/llvm/test/CodeGen/ARM/nomerge.ll b/llvm/test/CodeGen/ARM/nomerge.ll
@@ -42,6 +42,10 @@ define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       @ %bb.0: @ %entry
 ; CHECK-NEXT:    tst r0, #1
+; CHECK-NEXT:    beq .LBB1_2
+; CHECK-NEXT:  @ %bb.1: @ %if.then
+; CHECK-NEXT:    b bar
+; CHECK-NEXT:  .LBB1_2: @ %if.else
 ; CHECK-NEXT:    b bar
 entry:
   br i1 %i, label %if.then, label %if.else

diff --git a/llvm/test/CodeGen/LoongArch/nomerge.ll b/llvm/test/CodeGen/LoongArch/nomerge.ll
@@ -44,6 +44,10 @@ define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    andi $a0, $a0, 1
+; CHECK-NEXT:    beqz $a0, .LBB1_2
+; CHECK-NEXT:  # %bb.1: # %if.then
+; CHECK-NEXT:    b %plt(bar)
+; CHECK-NEXT:  .LBB1_2: # %if.else
 ; CHECK-NEXT:    b %plt(bar)
 entry:
   br i1 %i, label %if.then, label %if.else

diff --git a/llvm/test/CodeGen/RISCV/nomerge.ll b/llvm/test/CodeGen/RISCV/nomerge.ll
@@ -44,6 +44,10 @@ define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    andi a0, a0, 1
+; CHECK-NEXT:    beqz a0, .LBB1_2
+; CHECK-NEXT:  # %bb.1: # %if.then
+; CHECK-NEXT:    tail bar@plt
+; CHECK-NEXT:  .LBB1_2: # %if.else
 ; CHECK-NEXT:    tail bar@plt
 entry:
   br i1 %i, label %if.then, label %if.else

diff --git a/llvm/test/CodeGen/SystemZ/nomerge.ll b/llvm/test/CodeGen/SystemZ/nomerge.ll
@@ -41,6 +41,8 @@ define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    tmll %r2, 1
+; CHECK-NEXT:    jge bar@PLT
+; CHECK-NEXT:  .LBB1_1: # %if.then
 ; CHECK-NEXT:    jg bar@PLT
 entry:
   br i1 %i, label %if.then, label %if.else

diff --git a/llvm/test/CodeGen/X86/nomerge.ll b/llvm/test/CodeGen/X86/nomerge.ll
@@ -42,6 +42,8 @@ define void @foo_tail(i1 %i) nounwind {
 ; CHECK-LABEL: foo_tail:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    testb $1, %dil
+; CHECK-NEXT:    je bar # TAILCALL
+; CHECK-NEXT:  # %bb.1: # %if.then
 ; CHECK-NEXT:    jmp bar # TAILCALL
 entry:
   br i1 %i, label %if.then, label %if.else