radeon/llvm: Use a custom inserter to lower FABS

1 files changed, 16 insertions, 0 deletions

diff --git a/src/gallium/drivers/radeon/SIISelLowering.cpp b/src/gallium/drivers/radeon/SIISelLowering.cpp
index 4615db24266..e192af091b6 100644
--- a/src/gallium/drivers/radeon/SIISelLowering.cpp
+++ b/src/gallium/drivers/radeon/SIISelLowering.cpp
@@ -45,6 +45,22 @@ MachineBasicBlock * SITargetLowering::EmitInstrWithCustomInserter(
   switch (MI->getOpcode()) {
   default:
     return AMDGPUTargetLowering::EmitInstrWithCustomInserter(MI, BB);
+
+  case AMDIL::FABS_SI:
+    BuildMI(*BB, I, BB->findDebugLoc(I), TII->get(AMDIL::V_MOV_B32_e64))
+                 .addOperand(MI->getOperand(0))
+                 .addOperand(MI->getOperand(1))
+                /* VSRC1-2 are unused, but we still need to fill all the
+                 * operand slots, so we just reuse the VSRC0 operand */
+                 .addOperand(MI->getOperand(1))
+                 .addOperand(MI->getOperand(1))
+                 .addImm(1) // ABS
+                 .addImm(0) // CLAMP
+                 .addImm(0) // OMOD
+                 .addImm(0); // NEG
+    MI->eraseFromParent();
+    break;
+
   case AMDIL::SI_INTERP:
     LowerSI_INTERP(MI, *BB, I, MRI);
     break;