1 files changed, 21 insertions, 12 deletions

diff --git a/llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp b/llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
index a804a5e6d32..c4a06ef2230 100644
--- a/llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
+++ b/llvm/lib/Target/AMDGPU/SILowerControlFlow.cpp
@@ -78,7 +78,7 @@ private:
   void SkipIfDead(MachineInstr &MI);
 
   void If(MachineInstr &MI);
-  void Else(MachineInstr &MI);
+  void Else(MachineInstr &MI, bool ExecModified);
   void Break(MachineInstr &MI);
   void IfBreak(MachineInstr &MI);
   void ElseBreak(MachineInstr &MI);
@@ -215,7 +215,7 @@ void SILowerControlFlow::If(MachineInstr &MI) {
   MI.eraseFromParent();
 }
 
-void SILowerControlFlow::Else(MachineInstr &MI) {
+void SILowerControlFlow::Else(MachineInstr &MI, bool ExecModified) {
   MachineBasicBlock &MBB = *MI.getParent();
   DebugLoc DL = MI.getDebugLoc();
   unsigned Dst = MI.getOperand(0).getReg();
@@ -225,6 +225,15 @@ void SILowerControlFlow::Else(MachineInstr &MI) {
           TII->get(AMDGPU::S_OR_SAVEEXEC_B64), Dst)
           .addReg(Src); // Saved EXEC
 
+  if (ExecModified) {
+    // Adjust the saved exec to account for the modifications during the flow
+    // block that contains the ELSE. This can happen when WQM mode is switched
+    // off.
+    BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_AND_B64), Dst)
+            .addReg(AMDGPU::EXEC)
+            .addReg(Dst);
+  }
+
   BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_XOR_B64), AMDGPU::EXEC)
           .addReg(AMDGPU::EXEC)
           .addReg(Dst);
@@ -488,7 +497,6 @@ bool SILowerControlFlow::runOnMachineFunction(MachineFunction &MF) {
   SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
 
   bool HaveKill = false;
-  bool NeedWQM = false;
   bool NeedFlat = false;
   unsigned Depth = 0;
 
@@ -498,17 +506,24 @@ bool SILowerControlFlow::runOnMachineFunction(MachineFunction &MF) {
     MachineBasicBlock *EmptyMBBAtEnd = NULL;
     MachineBasicBlock &MBB = *BI;
     MachineBasicBlock::iterator I, Next;
+    bool ExecModified = false;
+
     for (I = MBB.begin(); I != MBB.end(); I = Next) {
       Next = std::next(I);
 
       MachineInstr &MI = *I;
-      if (TII->isWQM(MI) || TII->isDS(MI))
-        NeedWQM = true;
 
       // Flat uses m0 in case it needs to access LDS.
       if (TII->isFLAT(MI))
         NeedFlat = true;
 
+      for (const auto &Def : I->defs()) {
+        if (Def.isReg() && Def.isDef() && Def.getReg() == AMDGPU::EXEC) {
+          ExecModified = true;
+          break;
+        }
+      }
+
       switch (MI.getOpcode()) {
         default: break;
         case AMDGPU::SI_IF:
@@ -517,7 +532,7 @@ bool SILowerControlFlow::runOnMachineFunction(MachineFunction &MF) {
           break;
 
         case AMDGPU::SI_ELSE:
-          Else(MI);
+          Else(MI, ExecModified);
           break;
 
         case AMDGPU::SI_BREAK:
@@ -599,12 +614,6 @@ bool SILowerControlFlow::runOnMachineFunction(MachineFunction &MF) {
     }
   }
 
-  if (NeedWQM && MFI->getShaderType() == ShaderType::PIXEL) {
-    MachineBasicBlock &MBB = MF.front();
-    BuildMI(MBB, MBB.getFirstNonPHI(), DebugLoc(), TII->get(AMDGPU::S_WQM_B64),
-            AMDGPU::EXEC).addReg(AMDGPU::EXEC);
-  }
-
   if (NeedFlat && MFI->IsKernel) {
     // TODO: What to use with function calls?
     // We will need to Initialize the flat scratch register pair.