[PATCH] D60986: [WebAssembly] Bail out of fastisel earlier when computing PIC addresses

[Sam Clegg via Phabricator via llvm-commits]

sbc100 created this revision.
Herald added subscribers: llvm-commits, sunfish, aheejin, hiraditya, jgravelle-google, dschuff.
Herald added a project: LLVM.
sbc100 added a reviewer: dschuff.
sbc100 added a comment.

I have a test case that this fixes, that I'm currently trying to reduce.


This change partially reverts https://reviews.llvm.org/D54647 in favor
of bailing out during computeAddress instead.

This catches the condition earlier and handles more cases.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D60986

Files:
  llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp


Index: llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -151,7 +151,7 @@
     return MVT::INVALID_SIMPLE_VALUE_TYPE;
   }
   bool computeAddress(const Value *Obj, Address &Addr);
-  bool materializeLoadStoreOperands(Address &Addr);
+  void materializeLoadStoreOperands(Address &Addr);
   void addLoadStoreOperands(const Address &Addr, const MachineInstrBuilder &MIB,
                             MachineMemOperand *MMO);
   unsigned maskI1Value(unsigned Reg, const Value *V);
@@ -207,7 +207,6 @@
 } // end anonymous namespace
 
 bool WebAssemblyFastISel::computeAddress(const Value *Obj, Address &Addr) {
-
   const User *U = nullptr;
   unsigned Opcode = Instruction::UserOp1;
   if (const auto *I = dyn_cast<Instruction>(Obj)) {
@@ -230,6 +229,8 @@
       return false;
 
   if (const auto *GV = dyn_cast<GlobalValue>(Obj)) {
+    if (TLI.isPositionIndependent())
+      return false;
     if (Addr.getGlobalValue())
       return false;
     Addr.setGlobalValue(GV);
@@ -374,13 +375,10 @@
   return Addr.getReg() != 0;
 }
 
-bool WebAssemblyFastISel::materializeLoadStoreOperands(Address &Addr) {
+void WebAssemblyFastISel::materializeLoadStoreOperands(Address &Addr) {
   if (Addr.isRegBase()) {
     unsigned Reg = Addr.getReg();
     if (Reg == 0) {
-      const GlobalValue *GV = Addr.getGlobalValue();
-      if (GV && TLI.isPositionIndependent())
-        return false;
       Reg = createResultReg(Subtarget->hasAddr64() ? &WebAssembly::I64RegClass
                                                    : &WebAssembly::I32RegClass);
       unsigned Opc = Subtarget->hasAddr64() ? WebAssembly::CONST_I64
@@ -390,7 +388,6 @@
       Addr.setReg(Reg);
     }
   }
-  return true;
 }
 
 void WebAssemblyFastISel::addLoadStoreOperands(const Address &Addr,
@@ -1190,8 +1187,7 @@
     return false;
   }
 
-  if (!materializeLoadStoreOperands(Addr))
-    return false;
+  materializeLoadStoreOperands(Addr);
 
   unsigned ResultReg = createResultReg(RC);
   auto MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc),
@@ -1243,8 +1239,7 @@
     return false;
   }
 
-  if (!materializeLoadStoreOperands(Addr))
-    return false;
+  materializeLoadStoreOperands(Addr);
 
   unsigned ValueReg = getRegForValue(Store->getValueOperand());
   if (ValueReg == 0)


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