From 895d0585a89d3c17e269536322d62222f8c5730a Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Thu, 11 Feb 2021 15:52:44 -0600
Subject: [PATCH] Small new optimization: "anything % 1" equals 0.

---
 DAG.pas | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/DAG.pas b/DAG.pas
index 51f8a88..784057b 100644
--- a/DAG.pas
+++ b/DAG.pas
@@ -1638,7 +1638,13 @@ case op^.opcode of			{check for optimizations of this node}
 
    pc_mdl: begin			{pc_mdl}
       if op^.right^.opcode = pc_ldc then 
-         if op^.left^.opcode = pc_ldc then 
+         if op^.right^.lval = 1 then begin
+            if not SideEffects(op^.left) then begin
+               op^.right^.lval := 0;
+               opv := op^.right;
+               end; {if}
+            end {if}
+         else if op^.left^.opcode = pc_ldc then 
             if (op^.left^.lval >= 0) and (op^.right^.lval > 0) then begin
                op^.left^.lval := op^.left^.lval mod op^.right^.lval;
                opv := op^.left;
@@ -1647,7 +1653,13 @@ case op^.opcode of			{check for optimizations of this node}
 
    pc_mod: begin			{pc_mod}
       if op^.right^.opcode = pc_ldc then 
-         if op^.left^.opcode = pc_ldc then 
+         if op^.right^.q = 1 then begin
+            if not SideEffects(op^.left) then begin
+               op^.right^.q := 0;
+               opv := op^.right;
+               end; {if}
+            end {if}
+         else if op^.left^.opcode = pc_ldc then 
             if (op^.left^.q >= 0) and (op^.right^.q > 0) then begin
                op^.left^.q := op^.left^.q mod op^.right^.q;
                opv := op^.left;
@@ -2145,7 +2157,13 @@ case op^.opcode of			{check for optimizations of this node}
 
    pc_uim: begin			{pc_uim}
       if op^.right^.opcode = pc_ldc then 
-         if op^.left^.opcode = pc_ldc then 
+         if op^.right^.q = 1 then begin
+            if not SideEffects(op^.left) then begin
+               op^.right^.q := 0;
+               opv := op^.right;
+               end; {if}
+            end {if}
+         else if op^.left^.opcode = pc_ldc then 
             if op^.right^.q <> 0 then begin
                op^.left^.q :=
                   ord(umod(op^.left^.q & $0000FFFF, op^.right^.q & $0000FFFF));
@@ -2170,7 +2188,13 @@ case op^.opcode of			{check for optimizations of this node}
 
    pc_ulm: begin			{pc_ulm}
       if op^.right^.opcode = pc_ldc then 
-         if op^.left^.opcode = pc_ldc then 
+         if op^.right^.lval = 1 then begin
+            if not SideEffects(op^.left) then begin
+               op^.right^.lval := 0;
+               opv := op^.right;
+               end; {if}
+            end {if}
+         else if op^.left^.opcode = pc_ldc then 
             if op^.right^.lval <> 0 then begin
                op^.left^.lval := umod(op^.left^.lval, op^.right^.lval);
                opv := op^.left;