[llvm-commits] [llvm] r96822 - in /llvm/trunk: include/llvm/Target/TargetRegisterInfo.h lib/CodeGen/PrologEpilogInserter.cpp lib/Target/ARM/ARMBaseRegisterInfo.cpp lib/Target/ARM/ARMBaseRegisterInfo.h lib/Target/ARM/ARMInstrInfo.td lib/Target/ARM/ARMInstrThumb.td

Jim Grosbach grosbach at apple.com
Mon Feb 22 15:10:38 PST 2010


Author: grosbach
Date: Mon Feb 22 17:10:38 2010
New Revision: 96822

URL: http://llvm.org/viewvc/llvm-project?rev=96822&view=rev
Log:
Updated version of r96634 (which was reverted due to failing 176.gcc and
126.gcc nightly tests. These failures uncovered latent bugs that machine DCE
could remove one half of a stack adjust down/up pair, causing PEI to assert.
This update fixes that, and the tests now pass.

Modified:
    llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
    llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
    llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
    llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
    llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
    llvm/trunk/lib/Target/ARM/ARMInstrThumb.td

Modified: llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetRegisterInfo.h?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/Target/TargetRegisterInfo.h Mon Feb 22 17:10:38 2010
@@ -587,6 +587,17 @@
     return !hasFP(MF);
   }
 
+  /// canSimplifyCallFramePseudos - When possible, it's best to simplify the
+  /// call frame pseudo ops before doing frame index elimination. This is
+  /// possible only when frame index references between the pseudos won't
+  /// need adjusted for the call frame adjustments. Normally, that's true
+  /// if the function has a reserved call frame or a frame pointer. Some
+  /// targets (Thumb2, for example) may have more complicated criteria,
+  /// however, and can override this behavior.
+  virtual bool canSimplifyCallFramePseudos(MachineFunction &MF) const {
+    return hasReservedCallFrame(MF) || hasFP(MF);
+  }
+
   /// hasReservedSpillSlot - Return true if target has reserved a spill slot in
   /// the stack frame of the given function for the specified register. e.g. On
   /// x86, if the frame register is required, the first fixed stack object is

Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
+++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Mon Feb 22 17:10:38 2010
@@ -175,9 +175,10 @@
     MachineBasicBlock::iterator I = *i;
 
     // If call frames are not being included as part of the stack frame, and
-    // there is no dynamic allocation (therefore referencing frame slots off
-    // sp), leave the pseudo ops alone. We'll eliminate them later.
-    if (RegInfo->hasReservedCallFrame(Fn) || RegInfo->hasFP(Fn))
+    // the target doesn't indicate otherwise, remove the call frame pseudos
+    // here. The sub/add sp instruction pairs are still inserted, but we don't
+    // need to track the SP adjustment for frame index elimination.
+    if (RegInfo->canSimplifyCallFramePseudos(Fn))
       RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
   }
 }

Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.cpp Mon Feb 22 17:10:38 2010
@@ -1085,6 +1085,16 @@
   return !MF.getFrameInfo()->hasVarSizedObjects();
 }
 
+// canSimplifyCallFramePseudos - If there is a reserved call frame, the
+// call frame pseudos can be simplified. Unlike most targets, having a FP
+// is not sufficient here since we still may reference some objects via SP
+// even when FP is available in Thumb2 mode.
+bool ARMBaseRegisterInfo::
+canSimplifyCallFramePseudos(MachineFunction &MF) const {
+  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+  return hasReservedCallFrame(MF) || (AFI->isThumb1OnlyFunction() && hasFP(MF));
+}
+
 static void
 emitSPUpdate(bool isARM,
              MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,

Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h Mon Feb 22 17:10:38 2010
@@ -138,6 +138,7 @@
   virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const;
 
   virtual bool hasReservedCallFrame(MachineFunction &MF) const;
+  virtual bool canSimplifyCallFramePseudos(MachineFunction &MF) const;
 
   virtual void eliminateCallFramePseudoInstr(MachineFunction &MF,
                                              MachineBasicBlock &MBB,

Modified: llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrInfo.td?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrInfo.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrInfo.td Mon Feb 22 17:10:38 2010
@@ -635,7 +635,10 @@
                     i32imm:$size), NoItinerary,
            "${instid:label} ${cpidx:cpentry}", []>;
 
-let Defs = [SP], Uses = [SP] in {
+// FIXME: Marking these as hasSideEffects is necessary to prevent machine DCE
+// from removing one half of the matched pairs. That breaks PEI, which assumes
+// these will always be in pairs, and asserts if it finds otherwise. Better way?
+let Defs = [SP], Uses = [SP], hasSideEffects = 1 in {
 def ADJCALLSTACKUP :
 PseudoInst<(outs), (ins i32imm:$amt1, i32imm:$amt2, pred:$p), NoItinerary,
            "@ ADJCALLSTACKUP $amt1",

Modified: llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrThumb.td?rev=96822&r1=96821&r2=96822&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrThumb.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrThumb.td Mon Feb 22 17:10:38 2010
@@ -120,7 +120,10 @@
 //  Miscellaneous Instructions.
 //
 
-let Defs = [SP], Uses = [SP] in {
+// FIXME: Marking these as hasSideEffects is necessary to prevent machine DCE
+// from removing one half of the matched pairs. That breaks PEI, which assumes
+// these will always be in pairs, and asserts if it finds otherwise. Better way?
+let Defs = [SP], Uses = [SP], hasSideEffects = 1 in {
 def tADJCALLSTACKUP :
 PseudoInst<(outs), (ins i32imm:$amt1, i32imm:$amt2), NoItinerary,
            "@ tADJCALLSTACKUP $amt1",





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