Avoid errors from attempting common subexpression elimination on the left subexpression of the comma operator.

This could happen because the left subexpression does not produce a result for use in the enclosing expression, and therefore is not of the form expected by the CSE code.

The following program (derived from a csmith-generated test case) illustrates the problem:

#pragma optimize 16
int main(void) {
    int i;
    i, (i, 1);
}
This commit is contained in:
Stephen Heumann 2018-03-31 20:10:50 -05:00
parent fd0ff033ad
commit a9f7f97a2f
1 changed files with 4 additions and 2 deletions

View File

@ -2648,7 +2648,8 @@ var
begin {Match}
op2 := nil; {check for an exact match}
skip := false;
if CodesMatch(op, tree, true) then begin
if not (op^.opcode in [pc_str,pc_sro]) and CodesMatch(op, tree, true)
then begin
if op = tree then
op2 := tree
else begin
@ -2698,7 +2699,8 @@ var
if op^.right <> nil then
CheckTree(op^.right, bb);
if op^.next = nil then {look for a match to the current code}
if not (op^.opcode in [pc_cup,pc_cui,pc_tl1,pc_bno]) then begin
if not (op^.opcode in [pc_cup,pc_cui,pc_tl1,pc_bno,pc_pop,pc_sto,pc_sbf])
then begin
op2 := nil;
op3 := bb^.code;
while (op2 = nil) and (op3 <> nil) do begin