[llvm-commits] [llvm] r132981 - in /llvm/trunk: lib/CodeGen/AsmPrinter/AsmPrinter.cpp test/CodeGen/Thumb2/machine-licm.ll

[Rafael Espindola]

Author: rafael
Date: Tue Jun 14 01:08:32 2011
New Revision: 132981

URL: http://llvm.org/viewvc/llvm-project?rev=132981&view=rev
Log:
Implement Jakob's suggestion on how to detect fall thought without calling
AnalyzeBranch.

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    llvm/trunk/test/CodeGen/Thumb2/machine-licm.ll

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=132981&r1=132980&r2=132981&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Tue Jun 14 01:08:32 2011
@@ -1934,19 +1934,26 @@
   if (Pred->empty())
     return true;
 
-  // Otherwise, ask the backend.
-  const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
-  MachineBasicBlock *PredTBB = NULL, *PredFBB = NULL;
-  SmallVector<MachineOperand, 4> PredCond;
-  if (TII->AnalyzeBranch(*Pred, PredTBB, PredFBB, PredCond))
-    return false;
-
-  if (PredTBB == MBB || PredFBB == MBB)
-    return false;
-
-  // This is a fall through if there is no conditions in the bb
-  // or if there is no explicit false branch.
-  return PredCond.empty() || !PredFBB;
+  // Check the terminators in the previous blocks
+  for (MachineBasicBlock::iterator II = Pred->getFirstTerminator(),
+         IE = Pred->end(); II != IE; ++II) {
+    MachineInstr &MI = *II;
+
+    // If it is not a simple branch, we are in a table somewhere.
+    if (!MI.getDesc().isBranch() || MI.getDesc().isIndirectBranch())
+      return false;
+
+    // If we are the operands of one of the branches, this is not
+    // a fall through.
+    for (MachineInstr::mop_iterator OI = MI.operands_begin(),
+           OE = MI.operands_end(); OI != OE; ++OI) {
+      const MachineOperand& OP = *OI;
+      if (OP.isMBB() && OP.getMBB() == MBB)
+        return false;
+    }
+  }
+
+  return true;
 }
 
 

Modified: llvm/trunk/test/CodeGen/Thumb2/machine-licm.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/machine-licm.ll?rev=132981&r1=132980&r2=132981&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/machine-licm.ll (original)
+++ llvm/trunk/test/CodeGen/Thumb2/machine-licm.ll Tue Jun 14 01:08:32 2011
@@ -13,7 +13,7 @@
   br i1 %0, label %return, label %bb.nph
 
 bb.nph:                                           ; preds = %entry
-; CHECK: LBB0_1:
+; CHECK: BB#1
 ; CHECK: movw r[[R2:[0-9]+]], :lower16:L_GV$non_lazy_ptr
 ; CHECK: movt r[[R2]], :upper16:L_GV$non_lazy_ptr
 ; CHECK: ldr{{(.w)?}} r[[R2b:[0-9]+]], [r[[R2]]
@@ -21,7 +21,7 @@
 ; CHECK: LBB0_2
 ; CHECK-NOT: LCPI0_0:
 
-; PIC: LBB0_1:
+; PIC: BB#1
 ; PIC: movw r[[R2:[0-9]+]], :lower16:(L_GV$non_lazy_ptr-(LPC0_0+4))
 ; PIC: movt r[[R2]], :upper16:(L_GV$non_lazy_ptr-(LPC0_0+4))
 ; PIC: add r[[R2]], pc