ShuriZma
/
redream
mirror of https://github.com/inolen/redream.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add simplification of 0 identity element binary expressions 

Add remaining expression simplifications
This commit is contained in:
joseph 2016-12-15 00:09:31 -06:00 committed by Anthony Pesch
parent dfa90fac21
commit 3cb36fc6c4
1 changed files with 28 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
src/jit/ir/passes/expression_simplification_pass.c
View File

@ -5,19 +5,27 @@
DEFINE_STAT(zero_properties_removed, "Zero properties removed");
DEFINE_STAT(zero_identities_removed, "Zero identities removed");
DEFINE_STAT(one_identities_removed, "One identities removed");
DEFINE_STAT(bitwise_identities_removed, "Bitwise identities removed");
void esimp_run(struct ir *ir) {
list_for_each_entry(instr, &ir->instrs, struct ir_instr, it) {
/* TODO simplify bitwise identities */
/* x & x = x */
/* x | x = x */
/* x ^ x = 0 */
/* simplify bitwise identities with identical inputs */
if (instr->op == OP_XOR && instr->arg[0] == instr->arg[1]) {
struct ir_value *zero = ir_alloc_int(ir, 0, instr->result->type);
ir_replace_uses(instr->result, zero);
STAT_bitwise_identities_removed++;
} else if ((instr->op == OP_AND || instr->op == OP_OR) &&
instr->arg[0] == instr->arg[1]) {
ir_replace_uses(instr->result, instr->arg[0]);
STAT_bitwise_identities_removed++;
}
/* binary ops involving constants normally have the constant
argument as the second argument */
if (instr->arg[1] && ir_is_constant(instr->arg[1]) &&
ir_is_int(instr->arg[1]->type)) {
uint64_t rhs = ir_zext_constant(instr->arg[1]);
struct ir_value *lhs = instr->arg[0];
/* simplify binary ops where an argument of 0 always results in 0 */
if ((instr->op == OP_AND || instr->op == OP_SMUL ||
@ -28,17 +36,23 @@ void esimp_run(struct ir *ir) {
STAT_zero_properties_removed++;
}
/* TODO simplify binary ops where 0 is the identity element */
/* x + 0 = x */
/* x - 0 = x */
/* x | 0 = x */
/* x ^ 0 = x */
/* x << 0 = x */
/* x >> 0 = x */
/* simplify binary ops where 0 is an identity */
else if ((instr->op == OP_ADD || instr->op == OP_SUB ||
instr->op == OP_OR || instr->op == OP_XOR ||
instr->op == OP_SHL || instr->op == OP_LSHR ||
instr->op == OP_ASHR) &&
rhs == 0) {
ir_replace_uses(instr->result, lhs);
STAT_zero_identities_removed++;
}
/* TODO simplify binary ops where 1 is the identity element */
/* x * 1 = x */
/* x / 1 = x */
/* simplify binary ops where 1 is an identity */
else if ((instr->op == OP_UMUL || instr->op == OP_SMUL ||
instr->op == OP_DIV) &&
rhs == 1) {
ir_replace_uses(instr->result, lhs);
STAT_one_identities_removed++;
}
}
}
}