New optimization: Use unsigned rather than signed comparisons in some cases involving values that were originally unsigned bytes.

Specifically, convert signed word comparisons to unsigned if both sides were either unsigned byte values or non-negative constants. This is incorporated as part of intermediate code peephole optimization (bit 0).

This should alleviate some cases of performance regressions due to promoting char to int instead of unsigned int.
This commit is contained in:
Stephen Heumann 2016-01-01 21:58:44 -06:00
parent ab51fc228d
commit 5ab7c7876b

19
DAG.pas
View File

@ -26,6 +26,9 @@ procedure DAG (code: icptr);
{ parameters: }
{ code - opcode }
function TypeOf (op: icptr): baseTypeEnum;
{---------------------------------------------------------------}
implementation
@ -1493,14 +1496,22 @@ case op^.opcode of {check for optimizations of this node}
end; {else if}
end; {case pc_ixa}
pc_leq: begin {pc_leq}
if op^.optype in [cgWord,cgUWord] then
pc_leq, pc_les, pc_geq, pc_grt: begin {pc_leq, pc_les, pc_geq, pc_grt}
if (op^.opcode = pc_leq) and (op^.optype in [cgWord,cgUWord]) then
if op^.right^.opcode = pc_ldc then
if op^.right^.q < maxint then begin
op^.right^.q := op^.right^.q + 1;
op^.opcode := pc_les;
end; {if}
end; {case pc_lnm}
if (op^.optype = cgWord) then
if (TypeOf(op^.right) = cgUByte)
or ((op^.right^.opcode = pc_ldc) and (op^.right^.q >= 0)
and (op^.right^.optype in [cgByte,cgUByte,cgWord])) then
if (TypeOf(op^.left) = cgUByte)
or ((op^.left^.opcode = pc_ldc) and (op^.left^.q >= 0)
and (op^.left^.optype in [cgByte,cgUByte,cgWord])) then
op^.optype := cgUWord;
end; {case pc_leq, pc_les, pc_geq, pc_grt}
pc_lnd: begin {pc_lnd}
if op^.right^.opcode = pc_ldc then begin
@ -2168,7 +2179,7 @@ while list <> nil do begin
end; {Member}
function TypeOf (op: icptr): baseTypeEnum;
function TypeOf {(op: icptr): baseTypeEnum};
{ find the type for the expression tree }
{ }