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1 /*
2  * Copyright 2010 Tom Stellard <tstellar@gmail.com>
3  * SPDX-License-Identifier: MIT
4  */
5 
6 #include "util/u_math.h"
7 
8 #include "radeon_rename_regs.h"
9 
10 #include "radeon_compiler.h"
11 #include "radeon_list.h"
12 #include "radeon_program.h"
13 #include "radeon_variable.h"
14 
15 /**
16  * This function renames registers in an attempt to get the code close to
17  * SSA form.  After this function has completed, most of the register are only
18  * written to one time, with a few exceptions.
19  *
20  * This function assumes all the instructions are still of type
21  * RC_INSTRUCTION_NORMAL.
22  */
23 void
rc_rename_regs(struct radeon_compiler * c,void * user)24 rc_rename_regs(struct radeon_compiler *c, void *user)
25 {
26    struct rc_instruction *inst;
27    struct rc_list *variables;
28    struct rc_list *var_ptr;
29 
30    /* XXX Remove this once the register allocation works with flow control. */
31    for (inst = c->Program.Instructions.Next; inst != &c->Program.Instructions; inst = inst->Next) {
32       if (inst->U.I.Opcode == RC_OPCODE_BGNLOOP)
33          return;
34    }
35 
36    variables = rc_get_variables(c);
37 
38    for (var_ptr = variables; var_ptr; var_ptr = var_ptr->Next) {
39       int new_index;
40       unsigned writemask;
41       struct rc_variable *var = var_ptr->Item;
42 
43       if (var->Inst->U.I.DstReg.File != RC_FILE_TEMPORARY) {
44          continue;
45       }
46 
47       new_index = rc_find_free_temporary(c);
48       if (new_index < 0) {
49          rc_error(c, "Ran out of temporary registers\n");
50          return;
51       }
52 
53       writemask = rc_variable_writemask_sum(var);
54       rc_variable_change_dst(var, new_index, writemask);
55    }
56 }
57