cse.c - pub/scm/linux/kernel/git/viro/sparse - Git at Google

 /*
  * CSE - walk the linearized instruction flow, and
  * see if we can simplify it and apply CSE on it.
  *
  * Copyright (C) 2004 Linus Torvalds
  */

 #include <string.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <stddef.h>
 #include <assert.h>

 #include "parse.h"
 #include "expression.h"
 #include "linearize.h"
 #include "flow.h"

 #define INSN_HASH_SIZE 256
 static struct instruction_list *insn_hash_table[INSN_HASH_SIZE];

 int repeat_phase;

 static int phi_compare(pseudo_t phi1, pseudo_t phi2)
 {
 	const struct instruction *def1 = phi1->def;
 	const struct instruction *def2 = phi2->def;

 	if (def1->src1 != def2->src1)
 		return def1->src1 < def2->src1 ? -1 : 1;
 	if (def1->bb != def2->bb)
 		return def1->bb < def2->bb ? -1 : 1;
 	return 0;
 }


 static void clean_up_one_instruction(struct basic_block *bb, struct instruction *insn)
 {
 	unsigned long hash;

 	if (!insn->bb)
 		return;
 	assert(insn->bb == bb);
 	repeat_phase |= simplify_instruction(insn);
 	hash = (insn->opcode << 3) + (insn->size >> 3);
 	switch (insn->opcode) {
 	case OP_SEL:
 		hash += hashval(insn->src3);
 		/* Fall through */

 	/* Binary arithmetic */
 	case OP_ADD: case OP_SUB:
 	case OP_MULU: case OP_MULS:
 	case OP_DIVU: case OP_DIVS:
 	case OP_MODU: case OP_MODS:
 	case OP_SHL:
 	case OP_LSR: case OP_ASR:
 	case OP_AND: case OP_OR:

 	/* Binary logical */
 	case OP_XOR: case OP_AND_BOOL:
 	case OP_OR_BOOL:

 	/* Binary comparison */
 	case OP_SET_EQ: case OP_SET_NE:
 	case OP_SET_LE: case OP_SET_GE:
 	case OP_SET_LT: case OP_SET_GT:
 	case OP_SET_B:  case OP_SET_A:
 	case OP_SET_BE: case OP_SET_AE:
 		hash += hashval(insn->src2);
 		/* Fall through */

 	/* Unary */
 	case OP_NOT: case OP_NEG:
 		hash += hashval(insn->src1);
 		break;

 	case OP_SETVAL:
 		hash += hashval(insn->val);
 		break;

 	case OP_SYMADDR:
 		hash += hashval(insn->symbol);
 		break;

 	case OP_CAST:
 	case OP_SCAST:
 	case OP_PTRCAST:
 		/*
 		 * This is crap! Many "orig_types" are the
 		 * same as far as casts go, we should generate
 		 * some kind of "type hash" that is identical
 		 * for identical casts
 		 */
 		hash += hashval(insn->orig_type);
 		hash += hashval(insn->src);
 		break;

 	/* Other */
 	case OP_PHI: {
 		pseudo_t phi;
 		FOR_EACH_PTR(insn->phi_list, phi) {
 			struct instruction *def;
 			if (phi == VOID || !phi->def)
 				continue;
 			def = phi->def;
 			hash += hashval(def->src1);
 			hash += hashval(def->bb);
 		} END_FOR_EACH_PTR(phi);
 		break;
 	}

 	default:
 		/*
 		 * Nothing to do, don't even bother hashing them,
 		 * we're not going to try to CSE them
 		 */
 		return;
 	}
 	hash += hash >> 16;
 	hash &= INSN_HASH_SIZE-1;
 	add_instruction(insn_hash_table + hash, insn);
 }

 static void clean_up_insns(struct entrypoint *ep)
 {
 	struct basic_block *bb;

 	FOR_EACH_PTR(ep->bbs, bb) {
 		struct instruction *insn;
 		FOR_EACH_PTR(bb->insns, insn) {
 			clean_up_one_instruction(bb, insn);
 		} END_FOR_EACH_PTR(insn);
 	} END_FOR_EACH_PTR(bb);
 }

 /* Compare two (sorted) phi-lists */
 static int phi_list_compare(struct pseudo_list *l1, struct pseudo_list *l2)
 {
 	pseudo_t phi1, phi2;

 	PREPARE_PTR_LIST(l1, phi1);
 	PREPARE_PTR_LIST(l2, phi2);
 	for (;;) {
 		int cmp;

 		while (phi1 && (phi1 == VOID || !phi1->def))
 			NEXT_PTR_LIST(phi1);
 		while (phi2 && (phi2 == VOID || !phi2->def))
 			NEXT_PTR_LIST(phi2);

 		if (!phi1)
 			return phi2 ? -1 : 0;
 		if (!phi2)
 			return phi1 ? 1 : 0;
 		cmp = phi_compare(phi1, phi2);
 		if (cmp)
 			return cmp;
 		NEXT_PTR_LIST(phi1);
 		NEXT_PTR_LIST(phi2);
 	}
 	/* Not reached, but we need to make the nesting come out right */
 	FINISH_PTR_LIST(phi2);
 	FINISH_PTR_LIST(phi1);
 }

 static int insn_compare(const void *_i1, const void *_i2)
 {
 	const struct instruction *i1 = _i1;
 	const struct instruction *i2 = _i2;

 	if (i1->opcode != i2->opcode)
 		return i1->opcode < i2->opcode ? -1 : 1;

 	switch (i1->opcode) {
 	case OP_SEL:
 		if (i1->src3 != i2->src3)
 			return i1->src3 < i2->src3 ? -1 : 1;
 		/* Fall-through to binops */

 	/* Binary arithmetic */
 	case OP_ADD: case OP_SUB:
 	case OP_MULU: case OP_MULS:
 	case OP_DIVU: case OP_DIVS:
 	case OP_MODU: case OP_MODS:
 	case OP_SHL:
 	case OP_LSR: case OP_ASR:
 	case OP_AND: case OP_OR:

 	/* Binary logical */
 	case OP_XOR: case OP_AND_BOOL:
 	case OP_OR_BOOL:

 	/* Binary comparison */
 	case OP_SET_EQ: case OP_SET_NE:
 	case OP_SET_LE: case OP_SET_GE:
 	case OP_SET_LT: case OP_SET_GT:
 	case OP_SET_B:  case OP_SET_A:
 	case OP_SET_BE: case OP_SET_AE:
 		if (i1->src2 != i2->src2)
 			return i1->src2 < i2->src2 ? -1 : 1;
 		/* Fall through to unops */

 	/* Unary */
 	case OP_NOT: case OP_NEG:
 		if (i1->src1 != i2->src1)
 			return i1->src1 < i2->src1 ? -1 : 1;
 		break;

 	case OP_SYMADDR:
 		if (i1->symbol != i2->symbol)
 			return i1->symbol < i2->symbol ? -1 : 1;
 		break;

 	case OP_SETVAL:
 		if (i1->val != i2->val)
 			return i1->val < i2->val ? -1 : 1;
 		break;

 	/* Other */
 	case OP_PHI:
 		return phi_list_compare(i1->phi_list, i2->phi_list);

 	case OP_CAST:
 	case OP_SCAST:
 	case OP_PTRCAST:
 		/*
 		 * This is crap! See the comments on hashing.
 		 */
 		if (i1->orig_type != i2->orig_type)
 			return i1->orig_type < i2->orig_type ? -1 : 1;
 		if (i1->src != i2->src)
 			return i1->src < i2->src ? -1 : 1;
 		break;

 	default:
 		warning(i1->pos, "bad instruction on hash chain");
 	}
 	if (i1->size != i2->size)
 		return i1->size < i2->size ? -1 : 1;
 	return 0;
 }

 static void sort_instruction_list(struct instruction_list **list)
 {
 	sort_list((struct ptr_list **)list , insn_compare);
 }

 static struct instruction * cse_one_instruction(struct instruction *insn, struct instruction *def)
 {
 	convert_instruction_target(insn, def->target);

 	if (insn->opcode == OP_PHI) {
 		/* Remove the instruction from PHI users */
 		pseudo_t phi;
 		FOR_EACH_PTR(insn->phi_list, phi) {
 			struct pseudo_user *pu;
 			FOR_EACH_PTR(phi->users, pu) {
 				if (pu->insn == insn)
 					DELETE_CURRENT_PTR(pu);
 			} END_FOR_EACH_PTR(pu);
 		} END_FOR_EACH_PTR(phi);
 	}

 	insn->opcode = OP_NOP;
 	insn->bb = NULL;
 	repeat_phase |= REPEAT_CSE;
 	return def;
 }

 /*
  * Does "bb1" dominate "bb2"?
  */
 static int bb_dominates(struct entrypoint *ep, struct basic_block *bb1, struct basic_block *bb2, unsigned long generation)
 {
 	struct basic_block *parent;

 	/* Nothing dominates the entrypoint.. */
 	if (bb2 == ep->entry->bb)
 		return 0;
 	FOR_EACH_PTR(bb2->parents, parent) {
 		if (parent == bb1)
 			continue;
 		if (parent->generation == generation)
 			continue;
 		parent->generation = generation;
 		if (!bb_dominates(ep, bb1, parent, generation))
 			return 0;
 	} END_FOR_EACH_PTR(parent);
 	return 1;
 }

 static struct basic_block *trivial_common_parent(struct basic_block *bb1, struct basic_block *bb2)
 {
 	struct basic_block *parent;

 	if (bb_list_size(bb1->parents) != 1)
 		return NULL;
 	parent = first_basic_block(bb1->parents);
 	if (bb_list_size(bb2->parents) != 1)
 		return NULL;
 	if (first_basic_block(bb2->parents) != parent)
 		return NULL;
 	return parent;
 }

 static inline void remove_instruction(struct instruction_list **list, struct instruction *insn, int count)
 {
 	delete_ptr_list_entry((struct ptr_list **)list, insn, count);
 }

 static void add_instruction_to_end(struct instruction *insn, struct basic_block *bb)
 {
 	struct instruction *br = delete_last_instruction(&bb->insns);
 	insn->bb = bb;
 	add_instruction(&bb->insns, insn);
 	add_instruction(&bb->insns, br);
 }

 static struct instruction * try_to_cse(struct entrypoint *ep, struct instruction *i1, struct instruction *i2)
 {
 	struct basic_block *b1, *b2, *common;

 	/*
 	 * OK, i1 and i2 are the same instruction, modulo "target".
 	 * We should now see if we can combine them.
 	 */
 	b1 = i1->bb;
 	b2 = i2->bb;

 	/*
 	 * Currently we only handle the uninteresting degenerate case where
 	 * the CSE is inside one basic-block.
 	 */
 	if (b1 == b2) {
 		struct instruction *insn;
 		FOR_EACH_PTR(b1->insns, insn) {
 			if (insn == i1)
 				return cse_one_instruction(i2, i1);
 			if (insn == i2)
 				return cse_one_instruction(i1, i2);
 		} END_FOR_EACH_PTR(insn);
 		warning(b1->pos, "Whaa? unable to find CSE instructions");
 		return i1;
 	}
 	if (bb_dominates(ep, b1, b2, ++bb_generation))
 		return cse_one_instruction(i2, i1);

 	if (bb_dominates(ep, b2, b1, ++bb_generation))
 		return cse_one_instruction(i1, i2);

 	/* No direct dominance - but we could try to find a common ancestor.. */
 	common = trivial_common_parent(b1, b2);
 	if (common) {
 		i1 = cse_one_instruction(i2, i1);
 		remove_instruction(&b1->insns, i1, 1);
 		add_instruction_to_end(i1, common);
 	}

 	return i1;
 }

 void cleanup_and_cse(struct entrypoint *ep)
 {
 	int i;

 	simplify_memops(ep);
 repeat:
 	repeat_phase = 0;
 	clean_up_insns(ep);
 	for (i = 0; i < INSN_HASH_SIZE; i++) {
 		struct instruction_list **list = insn_hash_table + i;
 		if (*list) {
 			if (instruction_list_size(*list) > 1) {
 				struct instruction *insn, *last;

 				sort_instruction_list(list);

 				last = NULL;
 				FOR_EACH_PTR(*list, insn) {
 					if (!insn->bb)
 						continue;
 					if (last) {
 						if (!insn_compare(last, insn))
 							insn = try_to_cse(ep, last, insn);
 					}
 					last = insn;
 				} END_FOR_EACH_PTR(insn);
 			}
 			free_ptr_list((struct ptr_list **)list);
 		}
 	}

 	if (repeat_phase & REPEAT_SYMBOL_CLEANUP)
 		simplify_memops(ep);

 	if (repeat_phase & REPEAT_CSE)
 		goto repeat;
 }
	/*
	* CSE - walk the linearized instruction flow, and
	* see if we can simplify it and apply CSE on it.
	*
	* Copyright (C) 2004 Linus Torvalds
	*/

	#include <string.h>
	#include <stdarg.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <stddef.h>
	#include <assert.h>

	#include "parse.h"
	#include "expression.h"
	#include "linearize.h"
	#include "flow.h"

	#define INSN_HASH_SIZE 256
	static struct instruction_list *insn_hash_table[INSN_HASH_SIZE];

	int repeat_phase;

	static int phi_compare(pseudo_t phi1, pseudo_t phi2)
	{
	const struct instruction *def1 = phi1->def;
	const struct instruction *def2 = phi2->def;

	if (def1->src1 != def2->src1)
	return def1->src1 < def2->src1 ? -1 : 1;
	if (def1->bb != def2->bb)
	return def1->bb < def2->bb ? -1 : 1;
	return 0;
	}


	static void clean_up_one_instruction(struct basic_block bb, struct instruction insn)
	{
	unsigned long hash;

	if (!insn->bb)
	return;
	assert(insn->bb == bb);
	repeat_phase \|= simplify_instruction(insn);
	hash = (insn->opcode << 3) + (insn->size >> 3);
	switch (insn->opcode) {
	case OP_SEL:
	hash += hashval(insn->src3);
	/* Fall through */

	/* Binary arithmetic */
	case OP_ADD: case OP_SUB:
	case OP_MULU: case OP_MULS:
	case OP_DIVU: case OP_DIVS:
	case OP_MODU: case OP_MODS:
	case OP_SHL:
	case OP_LSR: case OP_ASR:
	case OP_AND: case OP_OR:

	/* Binary logical */
	case OP_XOR: case OP_AND_BOOL:
	case OP_OR_BOOL:

	/* Binary comparison */
	case OP_SET_EQ: case OP_SET_NE:
	case OP_SET_LE: case OP_SET_GE:
	case OP_SET_LT: case OP_SET_GT:
	case OP_SET_B: case OP_SET_A:
	case OP_SET_BE: case OP_SET_AE:
	hash += hashval(insn->src2);
	/* Fall through */

	/* Unary */
	case OP_NOT: case OP_NEG:
	hash += hashval(insn->src1);
	break;

	case OP_SETVAL:
	hash += hashval(insn->val);
	break;

	case OP_SYMADDR:
	hash += hashval(insn->symbol);
	break;

	case OP_CAST:
	case OP_SCAST:
	case OP_PTRCAST:
	/*
	* This is crap! Many "orig_types" are the
	* same as far as casts go, we should generate
	* some kind of "type hash" that is identical
	* for identical casts
	*/
	hash += hashval(insn->orig_type);
	hash += hashval(insn->src);
	break;

	/* Other */
	case OP_PHI: {
	pseudo_t phi;
	FOR_EACH_PTR(insn->phi_list, phi) {
	struct instruction *def;
	if (phi == VOID \|\| !phi->def)
	continue;
	def = phi->def;
	hash += hashval(def->src1);
	hash += hashval(def->bb);
	} END_FOR_EACH_PTR(phi);
	break;
	}

	default:
	/*
	* Nothing to do, don't even bother hashing them,
	* we're not going to try to CSE them
	*/
	return;
	}
	hash += hash >> 16;
	hash &= INSN_HASH_SIZE-1;
	add_instruction(insn_hash_table + hash, insn);
	}

	static void clean_up_insns(struct entrypoint *ep)
	{
	struct basic_block *bb;

	FOR_EACH_PTR(ep->bbs, bb) {
	struct instruction *insn;
	FOR_EACH_PTR(bb->insns, insn) {
	clean_up_one_instruction(bb, insn);
	} END_FOR_EACH_PTR(insn);
	} END_FOR_EACH_PTR(bb);
	}

	/* Compare two (sorted) phi-lists */
	static int phi_list_compare(struct pseudo_list l1, struct pseudo_list l2)
	{
	pseudo_t phi1, phi2;

	PREPARE_PTR_LIST(l1, phi1);
	PREPARE_PTR_LIST(l2, phi2);
	for (;;) {
	int cmp;

	while (phi1 && (phi1 == VOID \|\| !phi1->def))
	NEXT_PTR_LIST(phi1);
	while (phi2 && (phi2 == VOID \|\| !phi2->def))
	NEXT_PTR_LIST(phi2);

	if (!phi1)
	return phi2 ? -1 : 0;
	if (!phi2)
	return phi1 ? 1 : 0;
	cmp = phi_compare(phi1, phi2);
	if (cmp)
	return cmp;
	NEXT_PTR_LIST(phi1);
	NEXT_PTR_LIST(phi2);
	}
	/* Not reached, but we need to make the nesting come out right */
	FINISH_PTR_LIST(phi2);
	FINISH_PTR_LIST(phi1);
	}

	static int insn_compare(const void _i1, const void _i2)
	{
	const struct instruction *i1 = _i1;
	const struct instruction *i2 = _i2;

	if (i1->opcode != i2->opcode)
	return i1->opcode < i2->opcode ? -1 : 1;

	switch (i1->opcode) {
	case OP_SEL:
	if (i1->src3 != i2->src3)
	return i1->src3 < i2->src3 ? -1 : 1;
	/* Fall-through to binops */

	/* Binary arithmetic */
	case OP_ADD: case OP_SUB:
	case OP_MULU: case OP_MULS:
	case OP_DIVU: case OP_DIVS:
	case OP_MODU: case OP_MODS:
	case OP_SHL:
	case OP_LSR: case OP_ASR:
	case OP_AND: case OP_OR:

	/* Binary logical */
	case OP_XOR: case OP_AND_BOOL:
	case OP_OR_BOOL:

	/* Binary comparison */
	case OP_SET_EQ: case OP_SET_NE:
	case OP_SET_LE: case OP_SET_GE:
	case OP_SET_LT: case OP_SET_GT:
	case OP_SET_B: case OP_SET_A:
	case OP_SET_BE: case OP_SET_AE:
	if (i1->src2 != i2->src2)
	return i1->src2 < i2->src2 ? -1 : 1;
	/* Fall through to unops */

	/* Unary */
	case OP_NOT: case OP_NEG:
	if (i1->src1 != i2->src1)
	return i1->src1 < i2->src1 ? -1 : 1;
	break;

	case OP_SYMADDR:
	if (i1->symbol != i2->symbol)
	return i1->symbol < i2->symbol ? -1 : 1;
	break;

	case OP_SETVAL:
	if (i1->val != i2->val)
	return i1->val < i2->val ? -1 : 1;
	break;

	/* Other */
	case OP_PHI:
	return phi_list_compare(i1->phi_list, i2->phi_list);

	case OP_CAST:
	case OP_SCAST:
	case OP_PTRCAST:
	/*
	* This is crap! See the comments on hashing.
	*/
	if (i1->orig_type != i2->orig_type)
	return i1->orig_type < i2->orig_type ? -1 : 1;
	if (i1->src != i2->src)
	return i1->src < i2->src ? -1 : 1;
	break;

	default:
	warning(i1->pos, "bad instruction on hash chain");
	}
	if (i1->size != i2->size)
	return i1->size < i2->size ? -1 : 1;
	return 0;
	}

	static void sort_instruction_list(struct instruction_list **list)
	{
	sort_list((struct ptr_list **)list , insn_compare);
	}

	static struct instruction * cse_one_instruction(struct instruction insn, struct instruction def)
	{
	convert_instruction_target(insn, def->target);

	if (insn->opcode == OP_PHI) {
	/* Remove the instruction from PHI users */
	pseudo_t phi;
	FOR_EACH_PTR(insn->phi_list, phi) {
	struct pseudo_user *pu;
	FOR_EACH_PTR(phi->users, pu) {
	if (pu->insn == insn)
	DELETE_CURRENT_PTR(pu);
	} END_FOR_EACH_PTR(pu);
	} END_FOR_EACH_PTR(phi);
	}

	insn->opcode = OP_NOP;
	insn->bb = NULL;
	repeat_phase \|= REPEAT_CSE;
	return def;
	}

	/*
	* Does "bb1" dominate "bb2"?
	*/
	static int bb_dominates(struct entrypoint ep, struct basic_block bb1, struct basic_block *bb2, unsigned long generation)
	{
	struct basic_block *parent;

	/* Nothing dominates the entrypoint.. */
	if (bb2 == ep->entry->bb)
	return 0;
	FOR_EACH_PTR(bb2->parents, parent) {
	if (parent == bb1)
	continue;
	if (parent->generation == generation)
	continue;
	parent->generation = generation;
	if (!bb_dominates(ep, bb1, parent, generation))
	return 0;
	} END_FOR_EACH_PTR(parent);
	return 1;
	}

	static struct basic_block trivial_common_parent(struct basic_block bb1, struct basic_block *bb2)
	{
	struct basic_block *parent;

	if (bb_list_size(bb1->parents) != 1)
	return NULL;
	parent = first_basic_block(bb1->parents);
	if (bb_list_size(bb2->parents) != 1)
	return NULL;
	if (first_basic_block(bb2->parents) != parent)
	return NULL;
	return parent;
	}

	static inline void remove_instruction(struct instruction_list *list, struct instruction insn, int count)
	{
	delete_ptr_list_entry((struct ptr_list **)list, insn, count);
	}

	static void add_instruction_to_end(struct instruction insn, struct basic_block bb)
	{
	struct instruction *br = delete_last_instruction(&bb->insns);
	insn->bb = bb;
	add_instruction(&bb->insns, insn);
	add_instruction(&bb->insns, br);
	}

	static struct instruction * try_to_cse(struct entrypoint ep, struct instruction i1, struct instruction *i2)
	{
	struct basic_block b1, b2, *common;

	/*
	* OK, i1 and i2 are the same instruction, modulo "target".
	* We should now see if we can combine them.
	*/
	b1 = i1->bb;
	b2 = i2->bb;

	/*
	* Currently we only handle the uninteresting degenerate case where
	* the CSE is inside one basic-block.
	*/
	if (b1 == b2) {
	struct instruction *insn;
	FOR_EACH_PTR(b1->insns, insn) {
	if (insn == i1)
	return cse_one_instruction(i2, i1);
	if (insn == i2)
	return cse_one_instruction(i1, i2);
	} END_FOR_EACH_PTR(insn);
	warning(b1->pos, "Whaa? unable to find CSE instructions");
	return i1;
	}
	if (bb_dominates(ep, b1, b2, ++bb_generation))
	return cse_one_instruction(i2, i1);

	if (bb_dominates(ep, b2, b1, ++bb_generation))
	return cse_one_instruction(i1, i2);

	/* No direct dominance - but we could try to find a common ancestor.. */
	common = trivial_common_parent(b1, b2);
	if (common) {
	i1 = cse_one_instruction(i2, i1);
	remove_instruction(&b1->insns, i1, 1);
	add_instruction_to_end(i1, common);
	}

	return i1;
	}

	void cleanup_and_cse(struct entrypoint *ep)
	{
	int i;

	simplify_memops(ep);
	repeat:
	repeat_phase = 0;
	clean_up_insns(ep);
	for (i = 0; i < INSN_HASH_SIZE; i++) {
	struct instruction_list **list = insn_hash_table + i;
	if (*list) {
	if (instruction_list_size(*list) > 1) {
	struct instruction insn, last;

	sort_instruction_list(list);

	last = NULL;
	FOR_EACH_PTR(*list, insn) {
	if (!insn->bb)
	continue;
	if (last) {
	if (!insn_compare(last, insn))
	insn = try_to_cse(ep, last, insn);
	}
	last = insn;
	} END_FOR_EACH_PTR(insn);
	}
	free_ptr_list((struct ptr_list **)list);
	}
	}

	if (repeat_phase & REPEAT_SYMBOL_CLEANUP)
	simplify_memops(ep);

	if (repeat_phase & REPEAT_CSE)
	goto repeat;
	}