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If a conditional branch as an unconditional jump as target, that doesn't jump

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to a function-internal label, don't replace the jump target with the final
one, because this has no advantages and makes the code larger.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4367 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-10-15 10:21:50 +00:00
parent d9753c2eb7
commit 635fae97fb
2 changed files with 18 additions and 8 deletions
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2
src/cc65/codeopt.c
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@ -1674,7 +1674,6 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptBoolTrans, 1);
C += RunOptFunc (S, &DOptJumpTarget1, 1);
C += RunOptFunc (S, &DOptJumpTarget2, 1);
C += RunOptFunc (S, &DOptJumpTarget3, 1);
C += RunOptFunc (S, &DOptCondBranches1, 1);
C += RunOptFunc (S, &DOptCondBranches2, 1);
C += RunOptFunc (S, &DOptRTSJumps1, 1);
@ -1689,6 +1688,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptCmp9, 1);
C += RunOptFunc (S, &DOptTest1, 1);
C += RunOptFunc (S, &DOptLoad1, 1);
C += RunOptFunc (S, &DOptJumpTarget3, 1); /* After OptCondBranches2 */
C += RunOptFunc (S, &DOptUnusedLoads, 1);
C += RunOptFunc (S, &DOptUnusedStores, 1);
C += RunOptFunc (S, &DOptDupLoads, 1);

24
src/cc65/coptind.c
View File

@ -430,14 +430,24 @@ unsigned OptJumpCascades (CodeSeg* S)
/* Get this entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a branch, if it has a jump label, if this jump
* label is not attached to the instruction itself, and if the
* target instruction is itself a branch.
/* Check:
* - if it's a branch,
* - if it has a jump label,
* - if this jump label is not attached to the instruction itself,
* - if the target instruction is itself a branch,
* - if either the first branch is unconditional or the target of
* the second branch is internal to the function.
* The latter condition will avoid conditional branches to targets
* outside of the function (usually incspx), which won't simplify the
* code, since conditional far branches are emulated by a short branch
* around a jump.
*/
if ((E->Info & OF_BRA) != 0 &&
(OldLabel = E->JumpTo) != 0 &&
(N = OldLabel->Owner) != E &&
(N->Info & OF_BRA) != 0) {
if ((E->Info & OF_BRA) != 0 &&
(OldLabel = E->JumpTo) != 0 &&
(N = OldLabel->Owner) != E &&
(N->Info & OF_BRA) != 0 &&
((E->Info & OF_CBRA) == 0 ||
N->JumpTo != 0)) {
/* Check if we can use the final target label. This is the case,
* if the target branch is an absolut branch, or if it is a