[llvm] r265755 - Revert "[TargetRegisterInfo] Refactor the code to use BitMaskClassIterator."

[Quentin Colombet via llvm-commits]

Author: qcolombet
Date: Thu Apr  7 19:03:51 2016
New Revision: 265755

URL: http://llvm.org/viewvc/llvm-project?rev=265755&view=rev
Log:
Revert "[TargetRegisterInfo] Refactor the code to use BitMaskClassIterator."

This reverts commit r265734.
Looks like ASan is not happy about it.
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/11741

Looking.

Modified:
    llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp

Modified: llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp?rev=265755&r1=265754&r2=265755&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetRegisterInfo.cpp Thu Apr  7 19:03:51 2016
@@ -112,11 +112,18 @@ TargetRegisterInfo::getAllocatableClass(
   if (!RC || RC->isAllocatable())
     return RC;
 
-  for (BitMaskClassIterator It(RC->getSubClassMask(), *this); It.isValid();
-       ++It) {
-    const TargetRegisterClass *SubRC = getRegClass(It.getID());
-    if (SubRC->isAllocatable())
-      return SubRC;
+  const unsigned *SubClass = RC->getSubClassMask();
+  for (unsigned Base = 0, BaseE = getNumRegClasses();
+       Base < BaseE; Base += 32) {
+    unsigned Idx = Base;
+    for (unsigned Mask = *SubClass++; Mask; Mask >>= 1) {
+      unsigned Offset = countTrailingZeros(Mask);
+      const TargetRegisterClass *SubRC = getRegClass(Idx + Offset);
+      if (SubRC->isAllocatable())
+        return SubRC;
+      Mask >>= Offset;
+      Idx += Offset + 1;
+    }
   }
   return nullptr;
 }