svn commit: r276324 - projects/clang350-import/contrib/llvm/lib/Target/PowerPC

[Dimitry Andric]

Author: dim
Date: Sun Dec 28 02:30:03 2014
New Revision: 276324
URL: https://svnweb.freebsd.org/changeset/base/276324

Log:
  Pull in r224890 from upstream llvm trunk (by David Majnemer):
  
    PowerPC: CTR shouldn't fire if a TLS call is in the loop
  
    Determining the address of a TLS variable results in a function call in
    certain TLS models.  This means that a simple ICmpInst might actually
    result in invalidating the CTR register.
  
    In such cases, do not attempt to rely on the CTR register for loop
    optimization purposes.
  
    This fixes PR22034.
  
    Differential Revision: http://reviews.llvm.org/D6786
  
  This fixes a "Invalid PPC CTR loop" error when compiling parts of libc
  for PowerPC-32.

Modified:
  projects/clang350-import/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp

Modified: projects/clang350-import/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
==============================================================================
--- projects/clang350-import/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp	Sun Dec 28 00:53:52 2014	(r276323)
+++ projects/clang350-import/contrib/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp	Sun Dec 28 02:30:03 2014	(r276324)
@@ -194,6 +194,21 @@ static bool isLargeIntegerTy(bool Is32Bi
   return false;
 }
 
+// Determining the address of a TLS variable results in a function call in
+// certain TLS models.
+static bool memAddrUsesCTR(const PPCTargetMachine *TM,
+                           const llvm::Value *MemAddr) {
+  const auto *GV = dyn_cast<GlobalValue>(MemAddr);
+  if (!GV)
+    return false;
+  if (!GV->isThreadLocal())
+    return false;
+  if (!TM)
+    return true;
+  TLSModel::Model Model = TM->getTLSModel(GV);
+  return Model == TLSModel::GeneralDynamic || Model == TLSModel::LocalDynamic;
+}
+
 bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
   for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
        J != JE; ++J) {
@@ -390,6 +405,9 @@ bool PPCCTRLoops::mightUseCTR(const Trip
           SI->getNumCases()+1 >= (unsigned) TLI->getMinimumJumpTableEntries())
         return true;
     }
+    for (Value *Operand : J->operands())
+      if (memAddrUsesCTR(TM, Operand))
+        return true;
   }
 
   return false;