[ARM] Use DenseSet instead of DenseMap. NFC

[topperc]

The value in the map is set to "true" when something is added to the map.

Techncally this:

if (!DefRegs.contains(Reg))

will set the value in the map to false if it didn't already exist, and this is used to indicate the value wasn't in the map. This only occurs after all the "true" values have already been added to the map.

[llvmbot]

@llvm/pr-subscribers-backend-arm

Author: Craig Topper (topperc)

Changes

The value in the map is set to "true" when something is added to the map.

Techncally this:

if (!DefRegs.contains(Reg))

will set the value in the map to false if it didn't alrady exist, and this is used to indicate the value wasn't in the map. This only occurs after all the "true" values have already been added to the map.

---

Full diff: https://github.com/llvm/llvm-project/pull/131978.diff

1 Files Affected:

• (modified) llvm/lib/Target/ARM/ARMISelLowering.cpp (+3-3)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 1fb68fa85f7b6..234abefe75ee7 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -11366,12 +11366,12 @@ void ARMTargetLowering::EmitSjLjDispatchBlock(MachineInstr &MI,
            II = BB->rbegin(), IE = BB->rend(); II != IE; ++II) {
       if (!II->isCall()) continue;
 
-      DenseMap<unsigned, bool> DefRegs;
+      DenseSet<unsigned> DefRegs;
       for (MachineInstr::mop_iterator
              OI = II->operands_begin(), OE = II->operands_end();
            OI != OE; ++OI) {
         if (!OI->isReg()) continue;
-        DefRegs[OI->getReg()] = true;
+        DefRegs.insert(OI->getReg());
       }
 
       MachineInstrBuilder MIB(*MF, &*II);
@@ -11386,7 +11386,7 @@ void ARMTargetLowering::EmitSjLjDispatchBlock(MachineInstr &MI,
           continue;
         if (!Subtarget->isThumb() && !ARM::GPRRegClass.contains(Reg))
           continue;
-        if (!DefRegs[Reg])
+        if (!DefRegs.contains(Reg))
           MIB.addReg(Reg, RegState::ImplicitDefine | RegState::Dead);
       }
 

[kazutakahirata]

LGTM. Thanks!