PowerPC: Mark super regs of reserved regs reserved.

When a register like R1 is reserved, X1 should be reserved as well. This
was already done "manually" when 64bit code was enabled, however using
the markSuperRegs() function on the base register is more convenient and
allows to use the checksAllSuperRegsMarked() function even in 32bit mode
to avoid accidental breakage in the future.

This is also necessary to allow https://reviews.llvm.org/D28881

Differential Revision: https://reviews.llvm.org/D29056

llvm-svn: 292870

llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp

@@ -209,50 +209,38 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
 
   // The ZERO register is not really a register, but the representation of r0
   // when used in instructions that treat r0 as the constant 0.
-  Reserved.set(PPC::ZERO);
-  Reserved.set(PPC::ZERO8);
+  markSuperRegs(Reserved, PPC::ZERO);
 
   // The FP register is also not really a register, but is the representation
   // of the frame pointer register used by ISD::FRAMEADDR.
-  Reserved.set(PPC::FP);
-  Reserved.set(PPC::FP8);
+  markSuperRegs(Reserved, PPC::FP);
 
   // The BP register is also not really a register, but is the representation
   // of the base pointer register used by setjmp.
-  Reserved.set(PPC::BP);
-  Reserved.set(PPC::BP8);
+  markSuperRegs(Reserved, PPC::BP);
 
   // The counter registers must be reserved so that counter-based loops can
   // be correctly formed (and the mtctr instructions are not DCE'd).
-  Reserved.set(PPC::CTR);
-  Reserved.set(PPC::CTR8);
+  markSuperRegs(Reserved, PPC::CTR);
+  markSuperRegs(Reserved, PPC::CTR8);
 
-  Reserved.set(PPC::R1);
-  Reserved.set(PPC::LR);
-  Reserved.set(PPC::LR8);
-  Reserved.set(PPC::RM);
+  markSuperRegs(Reserved, PPC::R1);
+  markSuperRegs(Reserved, PPC::LR);
+  markSuperRegs(Reserved, PPC::LR8);
+  markSuperRegs(Reserved, PPC::RM);
 
   if (!Subtarget.isDarwinABI() || !Subtarget.hasAltivec())
-    Reserved.set(PPC::VRSAVE);
+    markSuperRegs(Reserved, PPC::VRSAVE);
 
   // The SVR4 ABI reserves r2 and r13
   if (Subtarget.isSVR4ABI()) {
-    Reserved.set(PPC::R2);  // System-reserved register
-    Reserved.set(PPC::R13); // Small Data Area pointer register
+    markSuperRegs(Reserved, PPC::R2);  // System-reserved register
+    markSuperRegs(Reserved, PPC::R13); // Small Data Area pointer register
   }
 
-  // On PPC64, r13 is the thread pointer. Never allocate this register.
   if (TM.isPPC64()) {
-    Reserved.set(PPC::R13);
-
-    Reserved.set(PPC::X1);
-    Reserved.set(PPC::X13);
-
-    if (TFI->needsFP(MF))
-      Reserved.set(PPC::X31);
-
-    if (hasBasePointer(MF))
-      Reserved.set(PPC::X30);
+    // On PPC64, r13 is the thread pointer. Never allocate this register.
+    markSuperRegs(Reserved, PPC::R13);
 
     // The 64-bit SVR4 ABI reserves r2 for the TOC pointer.
     if (Subtarget.isSVR4ABI()) {
@@ -262,33 +250,35 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
       // inline asm block, then we can treat r2 has an ordinary callee-saved
       // register.
       const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
-      if (FuncInfo->usesTOCBasePtr() || MF.hasInlineAsm())
-        Reserved.set(PPC::X2);
-      else
-        Reserved.reset(PPC::R2);
+      if (!FuncInfo->usesTOCBasePtr() && !MF.hasInlineAsm()) {
+        for (MCSuperRegIterator Super(PPC::R2, this, true); Super.isValid();
+             ++Super)
+          Reserved.reset(*Super);
+      }
     }
   }
 
   if (TFI->needsFP(MF))
-    Reserved.set(PPC::R31);
+    markSuperRegs(Reserved, PPC::R31);
 
   bool IsPositionIndependent = TM.isPositionIndependent();
   if (hasBasePointer(MF)) {
     if (Subtarget.isSVR4ABI() && !TM.isPPC64() && IsPositionIndependent)
-      Reserved.set(PPC::R29);
+      markSuperRegs(Reserved, PPC::R29);
     else
-      Reserved.set(PPC::R30);
+      markSuperRegs(Reserved, PPC::R30);
   }
 
   if (Subtarget.isSVR4ABI() && !TM.isPPC64() && IsPositionIndependent)
-    Reserved.set(PPC::R30);
+    markSuperRegs(Reserved, PPC::R30);
 
   // Reserve Altivec registers when Altivec is unavailable.
   if (!Subtarget.hasAltivec())
     for (TargetRegisterClass::iterator I = PPC::VRRCRegClass.begin(),
          IE = PPC::VRRCRegClass.end(); I != IE; ++I)
-      Reserved.set(*I);
+      markSuperRegs(Reserved, *I);
 
+  assert(checkAllSuperRegsMarked(Reserved));
   return Reserved;
 }