From 0c2477c26b530ad91c44814bf6fbea1c390ae7a6 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 4 Sep 2009 12:08:11 +0000
Subject: Include optional subclass flags, such as inbounds, nsw, etc., in the
 Constant uniquing tables. This allows distinct ConstantExpr objects with the
 same operation and different flags.

Even though a ConstantExpr "a + b" is either always overflowing or
never overflowing (due to being a ConstantExpr), it's still necessary
to be able to represent it both with and without overflow flags at
the same time within the IR, because the safety of the flag may
depend on the context of the use. If the constant really does overflow,
it wouldn't ever be safe to use with the flag set, however the use
may be in code that is never actually executed.

This also makes it possible to merge all the flags tests into a single test.

llvm-svn: 80998
---
 llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 56 +++++++++++++++++++------------
 1 file changed, 34 insertions(+), 22 deletions(-)

(limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp')

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 9ed75ab1313..05f7b52292d 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -883,19 +883,6 @@ bool BitcodeReader::ResolveGlobalAndAliasInits() {
   return false;
 }
 
-static void SetOptimizationFlags(Value *V, uint64_t Flags) {
-  if (OverflowingBinaryOperator *OBO =
-        dyn_cast<OverflowingBinaryOperator>(V)) {
-    if (Flags & (1 << bitc::OBO_NO_SIGNED_WRAP))
-      OBO->setHasNoSignedWrap(true);
-    if (Flags & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
-      OBO->setHasNoUnsignedWrap(true);
-  } else if (SDivOperator *Div = dyn_cast<SDivOperator>(V)) {
-    if (Flags & (1 << bitc::SDIV_EXACT))
-      Div->setIsExact(true);
-  }
-}
-
 bool BitcodeReader::ParseConstants() {
   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
     return Error("Malformed block record");
@@ -1047,10 +1034,22 @@ bool BitcodeReader::ParseConstants() {
       } else {
         Constant *LHS = ValueList.getConstantFwdRef(Record[1], CurTy);
         Constant *RHS = ValueList.getConstantFwdRef(Record[2], CurTy);
-        V = ConstantExpr::get(Opc, LHS, RHS);
+        unsigned Flags = 0;
+        if (Record.size() >= 4) {
+          if (Opc == Instruction::Add ||
+              Opc == Instruction::Sub ||
+              Opc == Instruction::Mul) {
+            if (Record[3] & (1 << bitc::OBO_NO_SIGNED_WRAP))
+              Flags |= OverflowingBinaryOperator::NoSignedWrap;
+            if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
+              Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
+          } else if (Opc == Instruction::SDiv) {
+            if (Record[3] & (1 << bitc::SDIV_EXACT))
+              Flags |= SDivOperator::IsExact;
+          }
+        }
+        V = ConstantExpr::get(Opc, LHS, RHS, Flags);
       }
-      if (Record.size() >= 4)
-        SetOptimizationFlags(V, Record[3]);
       break;
     }  
     case bitc::CST_CODE_CE_CAST: {  // CE_CAST: [opcode, opty, opval]
@@ -1075,10 +1074,12 @@ bool BitcodeReader::ParseConstants() {
         if (!ElTy) return Error("Invalid CE_GEP record");
         Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], ElTy));
       }
-      V = ConstantExpr::getGetElementPtr(Elts[0], &Elts[1], 
-                                               Elts.size()-1);
       if (BitCode == bitc::CST_CODE_CE_INBOUNDS_GEP)
-        cast<GEPOperator>(V)->setIsInBounds(true);
+        V = ConstantExpr::getInBoundsGetElementPtr(Elts[0], &Elts[1],
+                                                   Elts.size()-1);
+      else
+        V = ConstantExpr::getGetElementPtr(Elts[0], &Elts[1],
+                                           Elts.size()-1);
       break;
     }
     case bitc::CST_CODE_CE_SELECT:  // CE_SELECT: [opval#, opval#, opval#]
@@ -1610,8 +1611,19 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
       int Opc = GetDecodedBinaryOpcode(Record[OpNum++], LHS->getType());
       if (Opc == -1) return Error("Invalid BINOP record");
       I = BinaryOperator::Create((Instruction::BinaryOps)Opc, LHS, RHS);
-      if (OpNum < Record.size())
-        SetOptimizationFlags(I, Record[3]);
+      if (OpNum < Record.size()) {
+        if (Opc == Instruction::Add ||
+            Opc == Instruction::Sub ||
+            Opc == Instruction::Mul) {
+          if (Record[3] & (1 << bitc::OBO_NO_SIGNED_WRAP))
+            cast<BinaryOperator>(I)->setHasNoSignedWrap(true);
+          if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
+            cast<BinaryOperator>(I)->setHasNoUnsignedWrap(true);
+        } else if (Opc == Instruction::SDiv) {
+          if (Record[3] & (1 << bitc::SDIV_EXACT))
+            cast<BinaryOperator>(I)->setIsExact(true);
+        }
+      }
       break;
     }
     case bitc::FUNC_CODE_INST_CAST: {    // CAST: [opval, opty, destty, castopc]
@@ -1645,7 +1657,7 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
 
       I = GetElementPtrInst::Create(BasePtr, GEPIdx.begin(), GEPIdx.end());
       if (BitCode == bitc::FUNC_CODE_INST_INBOUNDS_GEP)
-        cast<GEPOperator>(I)->setIsInBounds(true);
+        cast<GetElementPtrInst>(I)->setIsInBounds(true);
       break;
     }
       
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