From: Tony Cook <tony@p250.dhcp.tony.develop-help.com>
Date: Mon, 18 Feb 2013 12:21:45 +0000 (+1100)
Subject: [rt #83212] avoid a possible bad optimizer on centos 5.9
X-Git-Tag: v0.94_01~29
X-Git-Url: http://git.imager.perl.org/imager.git/commitdiff_plain/1e9de315ee6bc5fc7bc990a81eb5662f1f8fcfff

[rt #83212] avoid a possible bad optimizer on centos 5.9

rotate(degrees => 270) was producing glitches near the horizontal and
vertical centrelines only on 5.9 with the default (perl config
specified) optimizations.  These disappeared when Imager was built with
-O1 instead.

Re-arranged some code to avoid duplicate floor() and double -> long
conversions which seems to have avoided the optimization problem.
---

diff --git a/rotate.im b/rotate.im
index be727505..64aa6a03 100644
--- a/rotate.im
+++ b/rotate.im
@@ -252,16 +252,18 @@ i_img *i_matrix_transform_bg(i_img *src, i_img_dim xsize, i_img_dim ysize, const
 	if (fabs(sz) > 0.0000001 
 	    && sx >= -1 && sx < src->xsize
 	    && sy >= -1 && sy < src->ysize) {
+	  i_img_dim bx = floor(sx);
+	  i_img_dim by = floor(sy);
 
 	  ROT_DEBUG(fprintf(stderr, "map " i_DFp " to %g,%g\n", i_DFcp(x, y), sx, sy));
-	  if (sx != (i_img_dim)sx) {
-	    if (sy != (i_img_dim)sy) {
+	  if (sx != bx) {
+	    if (sy != by) {
 	      IM_COLOR c[2][2]; 
 	      IM_COLOR ci2[2];
 	      ROT_DEBUG(fprintf(stderr, " both non-int\n"));
 	      for (i = 0; i < 2; ++i)
 		for (j = 0; j < 2; ++j)
-		  if (IM_GPIX(src, floor(sx)+i, floor(sy)+j, &c[j][i]))
+		  if (IM_GPIX(src, bx+i, by+j, &c[j][i]))
 		    c[j][i] = back;
 	      for (j = 0; j < 2; ++j)
 		ci2[j] = interp_i_color(c[j][0], c[j][1], sx, src->channels);
@@ -271,7 +273,7 @@ i_img *i_matrix_transform_bg(i_img *src, i_img_dim xsize, i_img_dim ysize, const
 	      IM_COLOR ci2[2];
 	      ROT_DEBUG(fprintf(stderr, " y int, x non-int\n"));
 	      for (i = 0; i < 2; ++i)
-		if (IM_GPIX(src, floor(sx)+i, sy, ci2+i))
+		if (IM_GPIX(src, bx+i, sy, ci2+i))
 		  ci2[i] = back;
 	      vals[x] = interp_i_color(ci2[0], ci2[1], sx, src->channels);
 	    }
@@ -281,7 +283,7 @@ i_img *i_matrix_transform_bg(i_img *src, i_img_dim xsize, i_img_dim ysize, const
 	      IM_COLOR ci2[2];
 	      ROT_DEBUG(fprintf(stderr, " x int, y non-int\n"));
 	      for (i = 0; i < 2; ++i)
-		if (IM_GPIX(src, sx, floor(sy)+i, ci2+i))
+		if (IM_GPIX(src, bx, by+i, ci2+i))
 		  ci2[i] = back;
 	      vals[x] = interp_i_color(ci2[0], ci2[1], sy, src->channels);
 	    }
@@ -402,7 +404,7 @@ i_matrix_mult(double *dest, const double *left, const double *right) {
 
 #define numfmt "%23g"
 
-ROT_DEBUG(static dump_mat(const char *name, double *f) {
+ROT_DEBUG(static void dump_mat(const char *name, double *f) {
   fprintf(stderr, "%s:\n  " numfmt " " numfmt " " numfmt "\n"
 	  "  " numfmt " " numfmt " " numfmt "\n"
 	  "  " numfmt " " numfmt " " numfmt "\n",
@@ -417,6 +419,8 @@ i_img *i_rotate_exact_bg(i_img *src, double amount,
   double temp[9], matrix[9];
   i_img_dim x1, x2, y1, y2, newxsize, newysize;
 
+  ROT_DEBUG(fprintf(stderr, "rotate angle %.20g\n", amount));
+
   /* first translate the centre of the image to (0,0) */
   xlate1[0] = 1;
   xlate1[2] = (src->xsize-1)/2.0;
diff --git a/t/t64copyflip.t b/t/t64copyflip.t
index 2632fd53..38561cc7 100644
--- a/t/t64copyflip.t
+++ b/t/t64copyflip.t
@@ -269,7 +269,7 @@ sub rot_test {
   is($deg->getwidth, 150, "check degrees => 270 width");
   is($deg->getheight, 150, "check degrees => 270 height");
   ok($deg->write(file => "testout/t64rotdeg270.ppm"), "save it");
-  # deg->write(file => "testout/t64rotright270.ppm");
+  $right->write(file => "testout/t64rotright270.ppm");
   is_image($deg, $right, "check right and degrees result the same");
   #$deg = $deg->convert(preset => "addalpha");
   # $right = $right->convert(preset => "addalpha");