commit 743d0a1f831f1d5a3141a6ca730558f40c35690a
author Alkis Evlogimenos <alkis@evlogimenos.com> Mon Feb 23 18:14:48 2004 +0000
committer Alkis Evlogimenos <alkis@evlogimenos.com> Mon Feb 23 18:14:48 2004 +0000
tree d2c1a5eefbfb5fc6922dab4d3dc29b3fb2f42242
parent fbc39d50455f1895117fe9796294942759026540

Refactor rewinding code for finding the first terminator of a basic
block into MachineBasicBlock::getFirstTerminator().

This also fixes a bug in the implementation of the above in both
RegAllocLocal and InstrSched, where instructions where added after the
terminator if the basic block's only instruction was a terminator (it
shouldn't matter for RegAllocLocal since this case never occurs in
practice).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11748 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineBasicBlock.cpp

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index 9d65453..89763ba 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -15,6 +15,8 @@
 #include "llvm/BasicBlock.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetMachine.h"
 #include "Support/LeakDetector.h"
 using namespace llvm;
 
@@ -56,6 +58,16 @@
             first->parent = toList.parent;
 }
 
+MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator()
+{
+  const TargetInstrInfo& TII = MachineFunction::get(
+    getBasicBlock()->getParent()).getTarget().getInstrInfo();
+  iterator I = end();
+  while (I != begin() && TII.isTerminatorInstr((--I)->getOpcode()));
+  if (I != end() && !TII.isTerminatorInstr(I->getOpcode())) ++I;
+  return I;
+}
+
 void MachineBasicBlock::dump() const
 {
     print(std::cerr);

lib/CodeGen/PHIElimination.cpp

diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index 0630582..ea464c9 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -143,22 +143,7 @@
       // source path the PHI.
       MachineBasicBlock &opBlock = *MI->getOperand(i).getMachineBasicBlock();
 
-      // Figure out where to insert the copy, which is at the end of the
-      // predecessor basic block, but before any terminator/branch
-      // instructions...
-      MachineBasicBlock::iterator I = opBlock.end();
-      if (I != opBlock.begin()) {  // Handle empty blocks
-        --I;
-        // must backtrack over ALL the branches in the previous block
-        while (MII.isTerminatorInstr(I->getOpcode()) &&
-               I != opBlock.begin())
-          --I;
-        
-        // move back to the first branch instruction so new instructions
-        // are inserted right in front of it and not in front of a non-branch
-        if (!MII.isTerminatorInstr(I->getOpcode()))
-          ++I;
-      }
+      MachineBasicBlock::iterator I = opBlock.getFirstTerminator();
       
       // Check to make sure we haven't already emitted the copy for this block.
       // This can happen because PHI nodes may have multiple entries for the

lib/CodeGen/RegAllocLocal.cpp

diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp
index 38e0073..a3d6639 100644
--- a/lib/CodeGen/RegAllocLocal.cpp
+++ b/lib/CodeGen/RegAllocLocal.cpp
@@ -649,11 +649,7 @@
     }
   }
 
-  // Rewind the iterator to point to the first flow control instruction...
-  const TargetInstrInfo &TII = TM->getInstrInfo();
-  MI = MBB.end();
-  while (MI != MBB.begin() && TII.isTerminatorInstr((--MI)->getOpcode()));
-  if (MI != MBB.end()) ++MI;
+  MI = MBB.getFirstTerminator();
 
   // Spill all physical registers holding virtual registers now.
   for (unsigned i = 0, e = RegInfo->getNumRegs(); i != e; ++i)