From 22d72f33d26baacc6048010f748e6dee240e9375 Mon Sep 17 00:00:00 2001 From: Bill Currie Date: Tue, 20 Nov 2012 15:22:05 +0900 Subject: [PATCH] Match pointer dereferences with pointer assignements. Having the source operand of a pointer assignment available to later instrctions can make for more efficient code as the value does not need to be dereferenced later. For this purpose, pointer dereference dag nodes now store the source operand as their value, and dagnode_match will match x=a.b with *(a+b)=y so long as both a and b are the same in both nodes. x and y are irrelevant to the match. The resulting code will be the equivalent of: *(a+b) = y; x = y; --- tools/qfcc/source/dags.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/tools/qfcc/source/dags.c b/tools/qfcc/source/dags.c index aca30db83..283907e86 100644 --- a/tools/qfcc/source/dags.c +++ b/tools/qfcc/source/dags.c @@ -234,6 +234,19 @@ node (operand_t *op) return node; } +static int +dagnode_deref_match (const dagnode_t *n, const daglabel_t *op, + dagnode_t *operands[3]) +{ + int i; + + for (i = 0; i < 2; i++) { + if (n->children[i + 1] != operands[i]) + return 0; + } + return 1; +} + static int dagnode_match (const dagnode_t *n, const daglabel_t *op, dagnode_t *operands[3]) @@ -242,6 +255,9 @@ dagnode_match (const dagnode_t *n, const daglabel_t *op, if (n->killed) return 0; + if (!strcmp (op->opcode, ".") + && n->label->opcode && !strcmp (n->label->opcode, ".=")) + return dagnode_deref_match (n, op, operands); if (n->label->opcode != op->opcode) return 0; for (i = 0; i < 3; i++) { @@ -624,6 +640,8 @@ dag_gencode (dag_t *dag, sblock_t *block, dagnode_t *dagnode) st = build_statement (dagnode->label->opcode, operands, dagnode->label->expr); sblock_add_statement (block, st); + // the source location is suitable for use in other nodes + dst = operands[0]; break; case st_move: case st_state: