diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
index 8eb710446ce..b2e0fb0436e 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp
@@ -3121,7 +3121,7 @@ Converter::handleInstruction(const struct tgsi_full_instruction *insn)
 
    Value *dst0[4], *rDst0[4];
    Value *src0, *src1, *src2, *src3;
-   Value *val0, *val1;
+   Value *val0 = NULL, *val1 = NULL;
    int c;
 
    tgsi = tgsi::Instruction(insn);
@@ -3415,6 +3415,8 @@ Converter::handleInstruction(const struct tgsi_full_instruction *insn)
    case TGSI_OPCODE_READ_INVOC:
       if (tgsi.getOpcode() == TGSI_OPCODE_READ_INVOC)
          src1 = fetchSrc(1, 0);
+      else
+         src1 = val0;
       FOR_EACH_DST_ENABLED_CHANNEL(0, c, tgsi) {
          geni = mkOp3(op, dstTy, dst0[c], fetchSrc(0, c), src1, mkImm(0x1f));
          geni->subOp = NV50_IR_SUBOP_SHFL_IDX;