CodeGen: Stop checking for physregs in constrainRegClass (#161795)

arsenm · web-flow · commit 2ff635dde236 · 2025-10-03T21:20:59.000+09:00
It's nonsensical to call this function on a physical register.
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -83,8 +83,6 @@ constrainRegClass(MachineRegisterInfo &MRI, Register Reg,
 
 const TargetRegisterClass *MachineRegisterInfo::constrainRegClass(
     Register Reg, const TargetRegisterClass *RC, unsigned MinNumRegs) {
-  if (Reg.isPhysical())
-    return nullptr;
   return ::constrainRegClass(*this, Reg, getRegClass(Reg), RC, MinNumRegs);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -83,8 +83,6 @@ constrainRegClass(MachineRegisterInfo &MRI, Register Reg,`
`83`	`83`
`84`	`84`	`const TargetRegisterClass *MachineRegisterInfo::constrainRegClass(`
`85`	`85`	`Register Reg, const TargetRegisterClass *RC, unsigned MinNumRegs) {`
`86`		`- if (Reg.isPhysical())`
`87`		`- return nullptr;`
`88`	`86`	`return ::constrainRegClass(*this, Reg, getRegClass(Reg), RC, MinNumRegs);`
`89`	`87`	`}`
`90`	`88`