fix aggressive loop optimizations

Previously, aggressive loop optimizations with a new compiler were not
possible due to undefined behaviour at end of arrays.

A macro "UBFIX" is added to allow ifdefs for fixes which resolve
undefined behavior. For example newer GCC versions will detect various
bugs in the original game code and will otherwise not compile with -Werror.

1 files changed, 22 insertions, 22 deletions

diff --git a/src/image_processing_effects.c b/src/image_processing_effects.c
index 13794faf0..cbd8b9b37 100644
--- a/src/image_processing_effects.c
+++ b/src/image_processing_effects.c
@@ -5,7 +5,7 @@
 
 // IWRAM common
 u8 gCanvasColumnStart;
-u16 (*gCanvasPixels)[][32];
+u16 *gCanvasPixels;
 u8 gCanvasRowEnd;
 u8 gCanvasHeight;
 u8 gCanvasColumnEnd;
@@ -125,7 +125,7 @@ static void ApplyImageEffect_RedChannelGrayscale(u8 delta)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -150,7 +150,7 @@ static void ApplyImageEffect_RedChannelGrayscaleHighlight(u8 highlight)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -179,7 +179,7 @@ static void ApplyImageEffect_Grayscale(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -195,7 +195,7 @@ static void ApplyImageEffect_Blur(void)
 
     for (i = 0; i < gCanvasColumnEnd; i++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[gCanvasRowStart * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart + i];
         u16 prevPixel = *pixel;
 
@@ -221,7 +221,7 @@ static void ApplyImageEffect_PersonalityColor(u8 personality)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -237,7 +237,7 @@ static void ApplyImageEffect_BlackAndWhite(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -255,7 +255,7 @@ static void ApplyImageEffect_BlackOutline(void)
     // Handle top row of pixels first.
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         pixel = &pixelRow[gCanvasColumnStart];
         *pixel = QuantizePixel_BlackOutline(pixel, pixel + 1);
         for (i = 1, pixel++; i < gCanvasColumnEnd - 1; i++, pixel++)
@@ -270,7 +270,7 @@ static void ApplyImageEffect_BlackOutline(void)
     // Handle each column from left to right.
     for (i = 0; i < gCanvasColumnEnd; i++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[gCanvasRowStart * gCanvasWidth];
         pixel = &pixelRow[gCanvasColumnStart + i];
         *pixel = QuantizePixel_BlackOutline(pixel, pixel + gCanvasWidth);
         for (j = 1, pixel += gCanvasWidth; j < gCanvasRowEnd - 1; j++, pixel += gCanvasWidth)
@@ -289,7 +289,7 @@ static void ApplyImageEffect_Invert(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -306,7 +306,7 @@ static void ApplyImageEffect_Shimmer(void)
     u16 prevPixel;
 
     // First, invert all of the colors.
-    pixel = (*gCanvasPixels)[0];
+    pixel = gCanvasPixels;
     for (i = 0; i < 64; i++)
     {
         for (j = 0; j < 64; j++, pixel++)
@@ -319,7 +319,7 @@ static void ApplyImageEffect_Shimmer(void)
     // Blur the pixels twice.
     for (j = 0; j < 64; j++)
     {
-        pixel = &(*gCanvasPixels)[0][j];
+        pixel = &gCanvasPixels[j];
         prevPixel = *pixel;
         *pixel = 0x8000;
         for (i = 1, pixel += 64; i < 63; i++, pixel += 64)
@@ -332,7 +332,7 @@ static void ApplyImageEffect_Shimmer(void)
         }
 
         *pixel = 0x8000;
-        pixel = &(*gCanvasPixels)[0][j];
+        pixel = &gCanvasPixels[j];
         prevPixel = *pixel;
         *pixel = 0x8000;
         for (i = 1, pixel += 64; i < 63; i++, pixel += 64)
@@ -350,7 +350,7 @@ static void ApplyImageEffect_Shimmer(void)
     // Finally, invert colors back to the original color space.
     // The above blur causes the outline areas to darken, which makes
     // this inversion give the effect of light outlines.
-    pixel = (*gCanvasPixels)[0];
+    pixel = gCanvasPixels;
     for (i = 0; i < 64; i++)
     {
         for (j = 0; j < 64; j++, pixel++)
@@ -367,7 +367,7 @@ static void ApplyImageEffect_BlurRight(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         u16 prevPixel = *pixel;
         for (i = 1, pixel++; i < gCanvasColumnEnd - 1; i++, pixel++)
@@ -387,7 +387,7 @@ static void ApplyImageEffect_BlurDown(void)
 
     for (i = 0; i < gCanvasColumnEnd; i++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][gCanvasRowStart * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[gCanvasRowStart * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart + i];
         u16 prevPixel = *pixel;
         for (j = 1, pixel += gCanvasWidth; j < gCanvasRowEnd - 1; j++, pixel += gCanvasWidth)
@@ -445,7 +445,7 @@ static void AddPointillismPoints(u16 arg0)
 
     for (i = 0; i < points[0].delta; i++)
     {
-        u16 *pixel = &(*gCanvasPixels)[points[i].row * 2][points[i].column];
+        u16 *pixel = &gCanvasPixels[points[i].row * 64] + points[i].column;
 
         if (!(0x8000 & *pixel))
         {
@@ -910,7 +910,7 @@ static void QuantizePalette_Standard(bool8 useLimitedPalette)
     gCanvasPalette[maxIndex] = RGB2(15, 15, 15);
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -978,7 +978,7 @@ static void QuantizePalette_BlackAndWhite(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -1009,7 +1009,7 @@ static void QuantizePalette_GrayscaleSmall(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -1027,7 +1027,7 @@ static void QuantizePalette_Grayscale(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {
@@ -1045,7 +1045,7 @@ static void QuantizePalette_PrimaryColors(void)
 
     for (j = 0; j < gCanvasRowEnd; j++)
     {
-        u16 *pixelRow = &(*gCanvasPixels)[0][(gCanvasRowStart + j) * gCanvasWidth];
+        u16 *pixelRow = &gCanvasPixels[(gCanvasRowStart + j) * gCanvasWidth];
         u16 *pixel = &pixelRow[gCanvasColumnStart];
         for (i = 0; i < gCanvasColumnEnd; i++, pixel++)
         {