From: Nate Begeman <natebegeman@mac.com>
Date: Sat, 26 Mar 2005 07:46:36 +0000 (+0000)
Subject: Get closer to having varargs working.  There's still something strange
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f7e43380354107a925dca1a1a4d7d7e70cab04e4;p=oota-llvm.git

Get closer to having varargs working.  There's still something strange
going on with copies between floating point and integer register files
being generated.  Once that is solved, varargs will be done.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20856 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 16955717f35..7ec033afb86 100644
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -132,7 +132,8 @@ PPC32TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
         needsLoad = true;
       }
       break;
-      case MVT::i64: ObjSize = 8; 
+      case MVT::i64: ObjSize = 8;
+      // FIXME: can split 64b load between reg/mem if it is last arg in regs
       if (GPR_remaining > 1) {
         BuildMI(&BB, PPC::IMPLICIT_DEF, 0, GPR[GPR_idx]);
         BuildMI(&BB, PPC::IMPLICIT_DEF, 0, GPR[GPR_idx+1]);
@@ -263,8 +264,9 @@ PPC32TargetLowering::LowerCallTo(SDOperand Chain,
       // register cannot be found for it.
       SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
       PtrOff = DAG.getNode(ISD::ADD, MVT::i32, StackPtr, PtrOff);
+      MVT::ValueType ArgVT = getValueType(Args[i].second);
       
-      switch (getValueType(Args[i].second)) {
+      switch (ArgVT) {
       default: assert(0 && "Unexpected ValueType for argument!");
       case MVT::i1:
       case MVT::i8:
@@ -287,27 +289,25 @@ PPC32TargetLowering::LowerCallTo(SDOperand Chain,
         ArgOffset += 4;
         break;
       case MVT::i64:
-        // If we have 2 or more GPRs, we won't do anything and let the ISD::CALL
-        // functionality in SelectExpr move pieces for us.
-        if (GPR_remaining > 1) {
-          SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, 
-            Args[i].first, DAG.getConstant(1, MVT::i32));
-          SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, 
-            Args[i].first, DAG.getConstant(0, MVT::i32));
-          args_to_use.push_back(Hi);          
-          args_to_use.push_back(Lo);          
-          GPR_remaining -= 2;
-        } else if (GPR_remaining > 0) {
+        // If we have one free GPR left, we can place the upper half of the i64
+        // in it, and store the other half to the stack.  If we have two or more
+        // free GPRs, then we can pass both halves of the i64 in registers.
+        if (GPR_remaining > 0) {
           SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, 
             Args[i].first, DAG.getConstant(1, MVT::i32));
           SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, 
             Args[i].first, DAG.getConstant(0, MVT::i32));
-          args_to_use.push_back(Hi);          
-          SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
-          PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
-          Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
-                                       Lo, PtrOff));
-          --GPR_remaining;
+          args_to_use.push_back(Hi);
+          if (GPR_remaining > 1) {
+            args_to_use.push_back(Lo);
+            GPR_remaining -= 2;
+          } else {
+            SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
+            PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
+            Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
+                                         Lo, PtrOff));
+            --GPR_remaining;
+          }
         } else {
           Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
                                        Args[i].first, PtrOff));
@@ -315,32 +315,33 @@ PPC32TargetLowering::LowerCallTo(SDOperand Chain,
         ArgOffset += 8;
         break;
       case MVT::f32:
-        if (FPR_remaining > 0 && GPR_remaining > 0 && isVarArg) {
-          --FPR_remaining;
-          ArgOffset += 4;
-        } else if (FPR_remaining > 0) {
-          args_to_use.push_back(Args[i].first);
-          --FPR_remaining;
-          if (GPR_remaining > 0) --GPR_remaining;
-        } else {
-          Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
-                                       Args[i].first, PtrOff));
-        }
-        ArgOffset += 4;
-        break;
       case MVT::f64:
-        if (FPR_remaining > 0 && GPR_remaining > 0 && isVarArg) {
-          --FPR_remaining;
-        } else if (FPR_remaining > 0) {
+        if (FPR_remaining > 0) {
+          if (isVarArg) {
+            // FIXME: Need FunctionType information so we can conditionally
+            // store only the non-fixed arguments in a vararg function.
+            Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
+                                         Args[i].first, PtrOff));
+            if (GPR_remaining > 0)
+              args_to_use.push_back(DAG.getLoad(MVT::i32, Chain, PtrOff));
+            if (GPR_remaining > 1) {
+              SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
+              PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
+              args_to_use.push_back(DAG.getLoad(MVT::i32, Chain, PtrOff));
+            }
+          }
           args_to_use.push_back(Args[i].first);
           --FPR_remaining;
+          // If we have any FPRs remaining, we may also have GPRs remaining.
+          // Args passed in FPRs consume either 1 (f32) or 2 (f64) available
+          // GPRs.
           if (GPR_remaining > 0) --GPR_remaining;
-          if (GPR_remaining > 0) --GPR_remaining;
+          if (GPR_remaining > 0 && MVT::f64 == ArgVT) --GPR_remaining;
         } else {
           Stores.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
                                        Args[i].first, PtrOff));
         }
-        ArgOffset += 8;
+        ArgOffset += (ArgVT == MVT::f32) ? 4 : 8;
         break;
       }
     }