[PATCH] [mips] Refactor saved-registers bitmask creation in MipsAsmPrinter::printSavedRegsBitmask. NFC.

[Toma Tabacu]

Hi dsanders,

Make the code more readable by fusing the for-loops together and explicitly checking for each register class.

Also, this version is more straightforward because it doesn't assume that FPU registers always come before CPU registers in the CalleeSavedInfo vector.

http://reviews.llvm.org/D8033

Files:
  lib/Target/Mips/MipsAsmPrinter.cpp

Index: lib/Target/Mips/MipsAsmPrinter.cpp
===================================================================
--- lib/Target/Mips/MipsAsmPrinter.cpp
+++ lib/Target/Mips/MipsAsmPrinter.cpp
@@ -259,33 +259,27 @@
   unsigned AFGR64RegSize = Mips::AFGR64RegClass.getSize();
   bool HasAFGR64Reg = false;
   unsigned CSFPRegsSize = 0;
-  unsigned i, e = CSI.size();
-
-  // Set FPU Bitmask.
-  for (i = 0; i != e; ++i) {
-    unsigned Reg = CSI[i].getReg();
-    if (Mips::GPR32RegClass.contains(Reg))
-      break;
 
+  for (const auto &I : CSI) {
+    unsigned Reg = I.getReg();
     unsigned RegNum =
         TM.getSubtargetImpl()->getRegisterInfo()->getEncodingValue(Reg);
+
+    // If it's a floating point register, set the FPU Bitmask.
+    if (Mips::FGR32RegClass.contains(Reg)) {
+      FPUBitmask |= (1 << RegNum);
+      CSFPRegsSize += FGR32RegSize;
+      continue;
+    }
     if (Mips::AFGR64RegClass.contains(Reg)) {
       FPUBitmask |= (3 << RegNum);
       CSFPRegsSize += AFGR64RegSize;
       HasAFGR64Reg = true;
       continue;
     }
-
-    FPUBitmask |= (1 << RegNum);
-    CSFPRegsSize += FGR32RegSize;
-  }
-
-  // Set CPU Bitmask.
-  for (; i != e; ++i) {
-    unsigned Reg = CSI[i].getReg();
-    unsigned RegNum =
-        TM.getSubtargetImpl()->getRegisterInfo()->getEncodingValue(Reg);
-    CPUBitmask |= (1 << RegNum);
+    // If it's a general purpose register, set the CPU Bitmask.
+    if (Mips::GPR32RegClass.contains(Reg))
+      CPUBitmask |= (1 << RegNum);
   }
 
   // FP Regs are saved right below where the virtual frame pointer points to.

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