From e035323ab40c59ed8f98be4401edcbbcbd18e180 Mon Sep 17 00:00:00 2001 From: uz Date: Sun, 13 Sep 2009 13:22:27 +0000 Subject: [PATCH] Added another condition that allows us to remove pha/pla. git-svn-id: svn://svn.cc65.org/cc65/trunk@4163 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- src/cc65/coptind.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/cc65/coptind.c b/src/cc65/coptind.c index 076e8fb73..5c0fe8d6c 100644 --- a/src/cc65/coptind.c +++ b/src/cc65/coptind.c @@ -1717,6 +1717,7 @@ unsigned OptPushPop (CodeSeg* S) unsigned Changes = 0; unsigned Push = 0; /* Index of push insn */ unsigned Pop = 0; /* Index of pop insn */ + unsigned ChgA = 0; /* Flag for A changed */ enum { Searching, FoundPush, @@ -1746,6 +1747,7 @@ unsigned OptPushPop (CodeSeg* S) if (E->OPC == OP65_PHA) { /* Found start of sequence */ Push = I; + ChgA = 0; State = FoundPush; } break; @@ -1754,6 +1756,7 @@ unsigned OptPushPop (CodeSeg* S) if (E->OPC == OP65_PHA) { /* Inner push/pop, restart */ Push = I; + ChgA = 0; } else if (E->OPC == OP65_PLA) { /* Found a matching pop */ Pop = I; @@ -1766,6 +1769,8 @@ unsigned OptPushPop (CodeSeg* S) /* Go into searching mode again */ State = Searching; } + } else if (E->Chg & REG_A) { + ChgA = 1; } break; @@ -1776,7 +1781,8 @@ unsigned OptPushPop (CodeSeg* S) * later, we may replace the PHA by the store and remove * pla if several other conditions are met. * - If this instruction is not a conditional branch, and A - * is unused later, we may remove PHA and PLA. + * is either unused later, or not changed by the code + * between push and pop, we may remove PHA and PLA. */ if (E->OPC == OP65_STA && !RegAUsed (S, I+1) && @@ -1799,7 +1805,7 @@ unsigned OptPushPop (CodeSeg* S) ++Changes; } else if ((E->Info & OF_CBRA) == 0 && - !RegAUsed (S, I)) { + (!RegAUsed (S, I) || !ChgA)) { /* We can remove the PHA and PLA instructions */ CS_DelEntry (S, Pop); -- 2.39.5