diff --git a/src/mesa/program/ir_to_mesa.cpp b/src/mesa/program/ir_to_mesa.cpp
index 8f75c82..16c454a 100644
--- a/src/mesa/program/ir_to_mesa.cpp
+++ b/src/mesa/program/ir_to_mesa.cpp
@@ -2622,8 +2622,9 @@ get_mesa_program(struct gl_context *ctx,
    GLenum target;
    const char *target_string;
    GLboolean progress;
+   gl_shader_type shaderType = _mesa_shader_type_to_index(shader->Type);
    struct gl_shader_compiler_options *options =
-         &ctx->ShaderCompilerOptions[_mesa_shader_type_to_index(shader->Type)];
+      &ctx->ShaderCompilerOptions[shaderType];
 
    switch (shader->Type) {
    case GL_VERTEX_SHADER:
@@ -2710,6 +2711,8 @@ get_mesa_program(struct gl_context *ctx,
    i = 0;
    foreach_iter(exec_list_iterator, iter, v.instructions) {
       const ir_to_mesa_instruction *inst = (ir_to_mesa_instruction *)iter.get();
+      const unsigned numSrc = _mesa_num_inst_src_regs(inst->op);
+      unsigned src;
 
       mesa_inst->Opcode = inst->op;
       mesa_inst->CondUpdate = inst->cond_update;
@@ -2720,9 +2723,22 @@ get_mesa_program(struct gl_context *ctx,
       mesa_inst->DstReg.CondMask = inst->dst_reg.cond_mask;
       mesa_inst->DstReg.WriteMask = inst->dst_reg.writemask;
       mesa_inst->DstReg.RelAddr = inst->dst_reg.reladdr != NULL;
-      mesa_inst->SrcReg[0] = mesa_src_reg_from_ir_src_reg(inst->src_reg[0]);
-      mesa_inst->SrcReg[1] = mesa_src_reg_from_ir_src_reg(inst->src_reg[1]);
-      mesa_inst->SrcReg[2] = mesa_src_reg_from_ir_src_reg(inst->src_reg[2]);
+      for (src = 0; src < numSrc; src++) {
+         if (!_mesa_valid_register_index(ctx, shaderType,
+                                         inst->src_reg[src].file,
+                                         inst->src_reg[src].index)) {
+            const char *regName =
+               _mesa_register_file_name(inst->src_reg[src].file);
+
+            fail_link(shader_program,
+                      "Register %s[%d] exceeds implementation limits.\n",
+                      regName, inst->src_reg[src].index);
+         }
+         else {
+            mesa_inst->SrcReg[src] =
+               mesa_src_reg_from_ir_src_reg(inst->src_reg[src]);
+         }
+      }
       mesa_inst->TexSrcUnit = inst->sampler;
       mesa_inst->TexSrcTarget = inst->tex_target;
       mesa_inst->TexShadow = inst->tex_shadow;
@@ -2733,7 +2749,7 @@ get_mesa_program(struct gl_context *ctx,
          prog->IndirectRegisterFiles |= 1 << mesa_inst->DstReg.File;
 
       /* Update program's bitmask of indirectly accessed register files */
-      for (unsigned src = 0; src < 3; src++)
+      for (src = 0; src < numSrc; src++)
          if (mesa_inst->SrcReg[src].RelAddr)
             prog->IndirectRegisterFiles |= 1 << mesa_inst->SrcReg[src].File;