patch to fix -O0 for Mips

[reed kotler]

We run the optimize pic phase in the case of -O0 also.

Previously this was not happening.


-------------- next part --------------
Index: test/CodeGen/Mips/optimize-pic-o0.ll
===================================================================
--- test/CodeGen/Mips/optimize-pic-o0.ll	(revision 0)
+++ test/CodeGen/Mips/optimize-pic-o0.ll	(revision 0)
@@ -0,0 +1,33 @@
+; RUN: llc -mtriple=mipsel -O0 < %s | FileCheck %s
+
+; Function Attrs: nounwind
+define i32 @main()  {
+entry:
+  %retval = alloca i32, align 4
+  %i = alloca i32, align 4
+  store i32 0, i32* %retval
+  store i32 0, i32* %i, align 4
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %0 = load i32* %i, align 4
+  %cmp = icmp slt i32 %0, 10
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  call void bitcast (void (...)* @foo to void ()*)()
+; CHECK: jalr $25
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %1 = load i32* %i, align 4
+  %inc = add nsw i32 %1, 1
+  store i32 %inc, i32* %i, align 4
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  %2 = load i32* %retval
+  ret i32 %2
+}
+
+declare void @foo(...) 
Index: lib/Target/Mips/MipsTargetMachine.cpp
===================================================================
--- lib/Target/Mips/MipsTargetMachine.cpp	(revision 203432)
+++ lib/Target/Mips/MipsTargetMachine.cpp	(working copy)
@@ -175,6 +175,9 @@
   virtual bool addInstSelector();
   virtual void addMachineSSAOptimization();
   virtual bool addPreEmitPass();
+
+  virtual bool addPreRegAlloc();
+
 };
 } // namespace
 
@@ -208,6 +211,15 @@
   TargetPassConfig::addMachineSSAOptimization();
 }
 
+bool MipsPassConfig::addPreRegAlloc() {
+  if (getOptLevel() == CodeGenOpt::None) {
+    addPass(createMipsOptimizePICCallPass(getMipsTargetMachine()));
+    return true;
+  }
+  else
+    return false;
+}
+
 void MipsTargetMachine::addAnalysisPasses(PassManagerBase &PM) {
   if (Subtarget.allowMixed16_32()) {
     DEBUG(errs() << "No ");