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Code Issues 1 Releases Wiki Activity

More work on x64 backend, especially branching.

Browse Source 
Needs changes to IR to allow encoding immediates in all
instructions where possible. This makes the IR denser, means
we don't need `constant` and `callk`, and allows certain optimizations
like comparing to zero, using `inc` and `dec`, etc which are
specializations of more general instructions with constants.
This commit is contained in:
Calvin Rose
2024-06-08 13:20:34 -05:00
parent 3995fa86e2
commit af10c1d4b5
5 changed files with 275 additions and 91 deletions
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2
examples/sysir/frontend.janet
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@@ -367,5 +367,5 @@
####
(compile1 myprog)
#(dump)
(dump)
(dumpx64)

4
src/boot/boot.janet
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@@ -2226,8 +2226,8 @@
(defn thaw
`Thaw an object (make it mutable) and do a deep copy, making
child value also mutable. Closures, fibers, and abstract
types will not be recursively thawed, but all other types will`
child values also mutable. Closures, fibers, and abstract
types will not be recursively thawed, but all other types will.`
[ds]
(case (type ds)
:array (walk-ind thaw ds)

7
src/core/sysir.c
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@@ -27,7 +27,7 @@
*/
/* TODO
* [ ] named fields (for debugging mostly)
* [ ] encode constants directly in 3 address codes - makes codegen easier
* [x] named registers and types
* [x] better type errors (perhaps mostly for compiler debugging - full type system goes on top)
* [ ] x86/x64 machine code target
@@ -87,7 +87,7 @@ static const JanetPrimName prim_names[] = {
{"void", JANET_PRIM_VOID},
};
static const char *prim_to_prim_name[] = {
const char *prim_to_prim_name[] = {
"u8",
"s8",
"u16",
@@ -1757,6 +1757,9 @@ static int sysir_gcmark(void *p, size_t s) {
if (ir->link_name != NULL) {
janet_mark(janet_wrap_string(ir->link_name));
}
janet_mark(janet_wrap_table(ir->labels));
janet_mark(janet_wrap_table(ir->register_name_lookup));
janet_mark(janet_wrap_abstract(ir->linkage));
return 0;
}

14
src/core/sysir.h
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@@ -126,6 +126,11 @@ typedef struct {
uint32_t type;
} JanetSysTypeField;
/* Allow read arguments to be constants to allow
* encoding immediates. This makes codegen easier. */
#define JANET_SYS_MAX_OPERAND 0x7FFFFFFFU
#define JANET_SYS_CONSTANT_PREFIX 0x80000000U
typedef struct {
JanetSysOp opcode;
union {
@@ -251,10 +256,19 @@ typedef struct {
JANET_SYS_SPILL_BOTH
} spills[3];
uint32_t regs[3];
uint32_t stack_offsets[3];
uint32_t stack_sizes[3];
} JanetSysSpill;
/* Delay alignment info for the most part to the lowering phase */
typedef struct {
uint32_t size;
uint32_t alignment;
} JanetSysTypeLayout;
/* Keep track of names for each instruction */
extern const char *janet_sysop_names[];
extern const char *prim_to_prim_name[];
/* Lowering */
void janet_sys_ir_lower_to_ir(JanetSysIRLinkage *linkage, JanetArray *into);

339
src/core/sysir_x86.c
View File

@@ -25,17 +25,64 @@
#include <janet.h>
#include "sysir.h"
#include "vector.h"
#include "util.h"
#endif
/*
* Wrap stuff up in a context struct
*/
static const char *register_names[] = {
"rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15"
};
static uint32_t v2reg(JanetTable *assignments, uint32_t var) {
return (uint32_t) janet_unwrap_number(janet_table_get(assignments, janet_wrap_number(var)));
/* Get the layout for types */
JanetSysTypeLayout get_x64layout(JanetSysTypeInfo info) {
JanetSysTypeLayout layout;
switch (info.prim) {
default:
layout.size = 1;
layout.alignment = 1;
break;
case JANET_PRIM_S8:
case JANET_PRIM_U8:
case JANET_PRIM_BOOLEAN:
layout.size = 1;
layout.alignment = 1;
break;
case JANET_PRIM_S16:
case JANET_PRIM_U16:
layout.size = 2;
layout.alignment = 2;
break;
case JANET_PRIM_S32:
case JANET_PRIM_U32:
layout.size = 4;
layout.alignment = 4;
break;
case JANET_PRIM_U64:
case JANET_PRIM_S64:
case JANET_PRIM_POINTER:
layout.size = 8;
layout.alignment = 8;
break;
case JANET_PRIM_F32:
case JANET_PRIM_F64:
layout.size = 8;
layout.alignment = 8;
break;
}
return layout;
}
JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
static uint32_t v2reg_dflt(JanetTable *assignments, uint32_t var, uint32_t dflt) {
Janet check = janet_table_get(assignments, janet_wrap_number(var));
if (janet_checktype(check, JANET_NUMBER)) {
return (uint32_t) janet_unwrap_number(check);
}
return dflt;
}
JanetSysSpill *assign_registers(JanetSysIR *ir,
JanetSysTypeLayout *layouts,
JanetTable *assignments,
uint32_t max_reg) {
/* simplest register assignment algorithm - first n variables
@@ -48,13 +95,19 @@ JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
for (uint32_t i = 0; i < ir->register_count; i++) {
if (i < max_reg) {
janet_table_put(assignments, janet_wrap_number(i), janet_wrap_number(i));
} else {
janet_table_put(assignments, janet_wrap_number(i), janet_wrap_number(max_reg));
}
}
// TODO - keep track of where we spill to. Simple idea would be to assign each variable
// a stack location.
/* Assign all slots a stack location */
/* TODO - be smarter about this */
uint32_t *stack_locations = janet_smalloc(ir->register_count * sizeof(uint32_t));
uint32_t next_loc = 0;
for (uint32_t i = 0; i < ir->register_count; i++) {
JanetSysTypeLayout layout = layouts[i];
next_loc = (next_loc + layout.alignment - 1) / layout.alignment * layout.alignment;
stack_locations[i] = next_loc;
next_loc += layout.size;
}
/* Generate spills. Spills occur iff using the temporary register (max_reg) */
JanetSysSpill *spills = NULL;
@@ -89,20 +142,26 @@ JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
case JANET_SYSOP_GTE:
case JANET_SYSOP_POINTER_ADD:
case JANET_SYSOP_POINTER_SUBTRACT:
rega = v2reg(assignments, instruction.three.dest);
regb = v2reg(assignments, instruction.three.lhs);
regc = v2reg(assignments, instruction.three.rhs);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, instruction.three.dest, max_reg);
regb = v2reg_dflt(assignments, instruction.three.lhs, max_reg + 1);
regc = v2reg_dflt(assignments, instruction.three.rhs, max_reg + 2);
spill.regs[0] = rega;
spill.regs[1] = regb;
spill.regs[2] = regc;
if (rega >= max_reg) {
spill.spills[0] = JANET_SYS_SPILL_WRITE;
spill.regs[0] = instruction.three.dest;
spill.stack_offsets[0] = stack_locations[instruction.three.dest];
spill.stack_sizes[0] = layouts[instruction.three.dest].size;
}
if (regb == max_reg) {
if (regb >= max_reg) {
spill.spills[1] = JANET_SYS_SPILL_READ;
spill.regs[1] = instruction.three.lhs;
spill.stack_offsets[1] = stack_locations[instruction.three.lhs];
spill.stack_sizes[1] = layouts[instruction.three.lhs].size;
}
if (regc == max_reg) {
if (regc >= max_reg) {
spill.spills[2] = JANET_SYS_SPILL_READ;
spill.regs[2] = instruction.three.rhs;
spill.stack_offsets[2] = stack_locations[instruction.three.rhs];
spill.stack_sizes[2] = layouts[instruction.three.rhs].size;
}
break;
@@ -110,41 +169,51 @@ JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
case JANET_SYSOP_MOVE:
case JANET_SYSOP_CAST:
case JANET_SYSOP_BNOT:
rega = v2reg(assignments, instruction.two.dest);
regb = v2reg(assignments, instruction.two.src);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, instruction.two.dest, max_reg);
regb = v2reg_dflt(assignments, instruction.two.src, max_reg + 1);
spill.regs[0] = rega;
spill.regs[1] = regb;
if (rega >= max_reg) {
spill.spills[0] = JANET_SYS_SPILL_WRITE;
spill.regs[0] = instruction.two.dest;
spill.stack_offsets[0] = stack_locations[instruction.two.dest];
spill.stack_sizes[0] = layouts[instruction.two.dest].size;
}
if (regb == max_reg) {
if (regb >= max_reg) {
spill.spills[1] = JANET_SYS_SPILL_READ;
spill.regs[1] = instruction.two.src;
spill.stack_offsets[1] = stack_locations[instruction.two.src];
spill.stack_sizes[1] = layouts[instruction.two.src].size;
}
break;
/* branch COND */
case JANET_SYSOP_BRANCH:
case JANET_SYSOP_BRANCH_NOT:
rega = v2reg(assignments, instruction.branch.cond);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, instruction.branch.cond, max_reg);
spill.regs[0] = rega;
if (rega >= max_reg) {
spill.spills[0] = JANET_SYS_SPILL_READ;
spill.regs[0] = instruction.branch.cond;
spill.stack_offsets[0] = stack_locations[instruction.branch.cond];
spill.stack_sizes[0] = layouts[instruction.branch.cond].size;
}
break;
case JANET_SYSOP_CONSTANT:
rega = v2reg(assignments, instruction.constant.dest);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, instruction.constant.dest, max_reg);
spill.regs[0] = rega;
if (rega >= max_reg) {
spill.spills[0] = JANET_SYS_SPILL_WRITE;
spill.regs[0] = instruction.constant.dest;
spill.stack_offsets[0] = stack_locations[instruction.constant.dest];
spill.stack_sizes[0] = layouts[instruction.constant.dest].size;
}
break;
case JANET_SYSOP_RETURN:
rega = v2reg(assignments, instruction.one.src);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, instruction.one.src, max_reg);
spill.regs[0] = rega;
if (rega >= max_reg) {
spill.spills[0] = JANET_SYS_SPILL_READ;
spill.regs[0] = instruction.one.src;
spill.stack_offsets[0] = stack_locations[instruction.one.src];
spill.stack_sizes[0] = layouts[instruction.one.src].size;
}
break;
@@ -152,10 +221,12 @@ JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
case JANET_SYSOP_ARG:
for (int j = 0; j < 3; j++) {
uint32_t var = instruction.arg.args[j];
rega = v2reg(assignments, var);
if (rega == max_reg) {
rega = v2reg_dflt(assignments, var, 0);
spill.regs[j] = rega;
if (rega >= max_reg) { /* Unused elements must be 0 */
spill.spills[j] = JANET_SYS_SPILL_READ;
spill.regs[j] = var;
spill.stack_offsets[j] = stack_locations[instruction.arg.args[j]];
spill.stack_sizes[j] = layouts[instruction.arg.args[j]].size;
}
}
break;
@@ -163,46 +234,88 @@ JanetSysSpill *assign_registers(JanetSysIR *ir, JanetTable *assignments,
/* Variable arg */
case JANET_SYSOP_CALL:
case JANET_SYSOP_CALLK:
/* TODO */
break;
}
janet_v_push(spills, spill);
}
janet_sfree(layouts);
janet_sfree(stack_locations);
return spills;
}
static void do_spills(JanetBuffer *buffer, JanetSysSpill *spills, uint32_t index) {
typedef struct {
uint32_t temps[3];
} JanetTempRegs;
static JanetTempRegs do_spills_read(JanetBuffer *buffer, JanetSysSpill *spills, uint32_t index) {
JanetSysSpill spill = spills[index];
JanetTempRegs temps;
for (int spi = 0; spi < 3; spi++) {
uint32_t reg = spill.regs[spi];
temps.temps[spi] = reg;
if (spill.spills[spi] == JANET_SYS_SPILL_READ || spill.spills[spi] == JANET_SYS_SPILL_BOTH) {
// emit load
uint32_t x = spill.stack_offsets[spi];
uint32_t s = spill.stack_sizes[spi];
janet_formatb(buffer, "load%u r%u from stack[%u] ; SPILL\n", s, reg, x);
}
}
return temps;
}
static void do_spills_write(JanetBuffer *buffer, JanetSysSpill *spills, uint32_t index) {
JanetSysSpill spill = spills[index];
for (int spi = 0; spi < 3; spi++) {
if (spill.spills[spi] == JANET_SYS_SPILL_WRITE || spill.spills[spi] == JANET_SYS_SPILL_BOTH) {
// emit store
uint32_t reg = spill.regs[spi];
void *x = (void *) 0x123456;
janet_formatb(buffer, "store r%u to %v ; SPILL\n", reg, janet_wrap_pointer(x));
}
if (spill.spills[spi] == JANET_SYS_SPILL_READ || spill.spills[spi] == JANET_SYS_SPILL_BOTH) {
// emit load
uint32_t reg = spill.regs[spi];
void *x = (void *) 0x123456;
janet_formatb(buffer, "load r%u from %v ; SPILL\n", reg, janet_wrap_pointer(x));
uint32_t x = spill.stack_offsets[spi];
uint32_t s = spill.stack_sizes[spi];
janet_formatb(buffer, "store%u r%u to stack[%u] ; SPILL\n", s, reg, x);
}
}
}
void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetBuffer *buffer) {
/* For now, emit assembly for nasm. Eventually an assembler for use with Janet would be good. */
JanetSysTypeLayout *all_layouts = janet_smalloc(linkage->type_def_count * sizeof(JanetSysTypeLayout));
for (uint32_t i = 0; i < linkage->type_def_count; i++) {
all_layouts[i] = get_x64layout(linkage->type_defs[i]);
}
/* Emit prelude */
janet_formatb(buffer, "bits 64\ndefault rel\n\n");
janet_formatb(buffer, "segment .text\n");
/* Do register allocation */
for (int32_t i = 0; i < linkage->ir_ordered->count; i++) {
JanetSysIR *ir = janet_unwrap_pointer(linkage->ir_ordered->data[i]);
JanetTable *assignments = janet_table(0);
/* 16 total 64 bit registers - 3 temp */
JanetSysSpill *spills = assign_registers(ir, assignments, 113);
JanetTempRegs temps;
/* Get type layouts */
JanetSysTypeLayout *layouts = janet_smalloc(ir->register_count * sizeof(JanetSysTypeLayout));
for (uint32_t i = 0; i < ir->register_count; i++) {
layouts[i] = all_layouts[ir->types[i]];
}
JanetSysSpill *spills = assign_registers(ir, layouts, assignments, 13);
/* Allow combining compare + branch instructions more easily */
int skip_branch = 0;
/* Emit constant strings */
for (int32_t j = 0; j < ir->constant_count; j++) {
janet_formatb(buffer, ".CONST%u:\n .string %p\n", j, ir->constants[j]);
}
/* Emit prelude */
if (ir->link_name != NULL) {
janet_formatb(buffer, ".%s\n", ir->link_name);
janet_formatb(buffer, "\n%s:\n", ir->link_name);
} else {
janet_formatb(buffer, "._section_%d\n", i);
janet_formatb(buffer, "\n_section_%d:\n", i);
}
for (uint32_t j = 0; j < ir->instruction_count; j++) {
JanetSysInstruction instruction = ir->instructions[j];
@@ -225,34 +338,34 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetBuffer *buffer)
case JANET_SYSOP_SUBTRACT:
case JANET_SYSOP_MULTIPLY:
case JANET_SYSOP_DIVIDE:
do_spills(buffer, spills, j);
temps = do_spills_read(buffer, spills, j);
janet_formatb(buffer, "r%u = %s r%u, r%u\n",
v2reg(assignments, instruction.three.dest),
temps.temps[0],
janet_sysop_names[instruction.opcode],
v2reg(assignments, instruction.three.lhs),
v2reg(assignments, instruction.three.rhs));
temps.temps[1],
temps.temps[2]);
do_spills_write(buffer, spills, j);
break;
case JANET_SYSOP_MOVE:
do_spills(buffer, spills, j);
janet_formatb(buffer, "r%u = r%u\n",
v2reg(assignments, instruction.two.dest),
v2reg(assignments, instruction.two.src));
temps = do_spills_read(buffer, spills, j);
//janet_formatb(buffer, "r%u = r%u\n", temps.temps[0], temps.temps[1]);
janet_formatb(buffer, "mov %s, %s\n",
register_names[temps.temps[0]],
register_names[temps.temps[1]]);
do_spills_write(buffer, spills, j);
break;
case JANET_SYSOP_RETURN:
do_spills(buffer, spills, j);
janet_formatb(buffer, "return r%u\n",
v2reg(assignments, instruction.one.src));
temps = do_spills_read(buffer, spills, j);
//janet_formatb(buffer, "return r%u\n", temps.temps[0]);
janet_formatb(buffer, "leave\n mov %s, rax\nret\n", register_names[temps.temps[0]]);
break;
case JANET_SYSOP_CONSTANT:
do_spills(buffer, spills, j);
janet_formatb(buffer, "r%u = constant $%v\n",
v2reg(assignments, instruction.constant.dest),
ir->constants[instruction.constant.constant]);
temps = do_spills_read(buffer, spills, j);
janet_formatb(buffer, "r%u = constant $%v\n", temps.temps[0], ir->constants[instruction.constant.constant]);
do_spills_write(buffer, spills, j);
break;
case JANET_SYSOP_LABEL:
do_spills(buffer, spills, j);
janet_formatb(buffer, "label_%u:\n",
v2reg(assignments, instruction.label.id));
janet_formatb(buffer, "label_%u:\n", instruction.label.id);
break;
case JANET_SYSOP_EQ:
case JANET_SYSOP_NEQ:
@@ -260,19 +373,74 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetBuffer *buffer)
case JANET_SYSOP_LTE:
case JANET_SYSOP_GT:
case JANET_SYSOP_GTE:
do_spills(buffer, spills, j);
janet_formatb(buffer, "r%u = %s r%u, r%u\n",
v2reg(assignments, instruction.three.dest),
janet_sysop_names[instruction.opcode],
v2reg(assignments, instruction.three.lhs),
v2reg(assignments, instruction.three.rhs));
temps = do_spills_read(buffer, spills, j);
JanetSysInstruction nexti = ir->instructions[j + 1];
/* Combine compare and branch into one instruction */
/* TODO - handle when lhs or rhs is 0 */
/* TODO - handle floats */
janet_formatb(buffer, "cmp %s, %s\n", register_names[temps.temps[1]], register_names[temps.temps[2]]);
if ((nexti.opcode == JANET_SYSOP_BRANCH ||
nexti.opcode == JANET_SYSOP_BRANCH_NOT)
&& nexti.branch.cond == instruction.three.dest) {
skip_branch = 1;
int invert = nexti.opcode == JANET_SYSOP_BRANCH_NOT;
if (instruction.opcode == JANET_SYSOP_EQ) {
janet_formatb(buffer, "%s label_%u\n", invert ? "jne" : "je", nexti.branch.to);
} else if (instruction.opcode == JANET_SYSOP_NEQ) {
janet_formatb(buffer, "%s label_%u\n", invert ? "je" : "jne", nexti.branch.to);
} else if (instruction.opcode == JANET_SYSOP_GT) {
janet_formatb(buffer, "%s label_%u\n", invert ? "jle" : "jg", nexti.branch.to);
} else if (instruction.opcode == JANET_SYSOP_GTE) {
janet_formatb(buffer, "%s label_%u\n", invert ? "jl" : "jge", nexti.branch.to);
} else if (instruction.opcode == JANET_SYSOP_LT) {
janet_formatb(buffer, "%s label_%u\n", invert ? "jge" : "jl", nexti.branch.to);
} else if (instruction.opcode == JANET_SYSOP_LTE) {
janet_formatb(buffer, "%s label_%u\n", invert ? "jg" : "jle", nexti.branch.to);
} else {
janet_panic("unreachable");
}
do_spills_write(buffer, spills, j);
break;
}
/* Fallback to set* instructions */
if (instruction.opcode == JANET_SYSOP_EQ) {
janet_formatb(buffer, "sete %s\n", register_names[temps.temps[0]]);
} else if (instruction.opcode == JANET_SYSOP_NEQ) {
janet_formatb(buffer, "setne %s\n", register_names[temps.temps[0]]);
} else if (instruction.opcode == JANET_SYSOP_GT) {
janet_formatb(buffer, "setg %s\n", register_names[temps.temps[0]]);
} else if (instruction.opcode == JANET_SYSOP_GTE) {
janet_formatb(buffer, "setge %s\n", register_names[temps.temps[0]]);
} else if (instruction.opcode == JANET_SYSOP_LT) {
janet_formatb(buffer, "setl %s\n", register_names[temps.temps[0]]);
} else if (instruction.opcode == JANET_SYSOP_LTE) {
janet_formatb(buffer, "setle %s\n", register_names[temps.temps[0]]);
} else {
janet_panic("unreachable");
}
do_spills_write(buffer, spills, j);
break;
case JANET_SYSOP_BRANCH:
case JANET_SYSOP_BRANCH_NOT:
do_spills(buffer, spills, j);
janet_formatb(buffer, "branch label_%u if r%u\n",
instruction.branch.to,
v2reg(assignments, instruction.branch.cond));
;
if (skip_branch) {
skip_branch = 0;
break;
}
temps = do_spills_read(buffer, spills, j);
if (instruction.opcode == JANET_SYSOP_BRANCH) {
janet_formatb(buffer, "jnz %s label_%u\n",
register_names[temps.temps[0]],
instruction.branch.to);
} else {
janet_formatb(buffer, "jz %s label_%u\n",
register_names[temps.temps[0]],
instruction.branch.to);
}
break;
case JANET_SYSOP_JUMP:
janet_formatb(buffer, "jmp label_%u\n",
instruction.jump.to);
break;
case JANET_SYSOP_CALLK:
case JANET_SYSOP_CALL:
@@ -284,15 +452,15 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetBuffer *buffer)
while (offset * 3 + sub_count >= (int32_t) instruction.call.arg_count) {
sub_count--;
}
JanetSysInstruction arg_instruction = ir->instructions[j + offset];
do_spills(buffer, spills, j + offset);
temps = do_spills_read(buffer, spills, j + offset);
for (int x = sub_count; x >= 0; x--) {
janet_formatb(buffer, "push r%u\n", v2reg(assignments, arg_instruction.arg.args[x]));
janet_formatb(buffer, "push r%u\n", temps.temps[x]);
}
}
temps = do_spills_read(buffer, spills, j);
if (instruction.opcode == JANET_SYSOP_CALLK) {
if (instruction.callk.has_dest) {
janet_formatb(buffer, "r%u = call %p\n", v2reg(assignments, instruction.callk.dest),
janet_formatb(buffer, "r%u = call %p\n", temps.temps[0],
ir->constants[instruction.callk.constant]);
} else {
janet_formatb(buffer, "call %p\n",
@@ -300,13 +468,12 @@ void janet_sys_ir_lower_to_x64(JanetSysIRLinkage *linkage, JanetBuffer *buffer)
}
} else {
if (instruction.call.has_dest) {
janet_formatb(buffer, "r%u = call r%u\n", v2reg(assignments, instruction.call.dest),
v2reg(assignments, instruction.call.callee));
janet_formatb(buffer, "r%u = call r%u\n", temps.temps[0], temps.temps[1]);
} else {
janet_formatb(buffer, "call r%u\n",
v2reg(assignments, instruction.call.callee));
janet_formatb(buffer, "call r%u\n", temps.temps[0]);
}
}
do_spills_write(buffer, spills, j);
break;
// On a comparison, if next instruction is branch that reads from dest, combine into a single op.
}