[PATCH v2 2/2] gdiplus: improve performance of matrix multiplication by unrolling loop

[Bartosz Kosiorek]

From: Bartosz Kosiorek

---
 dlls/gdiplus/matrix.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/dlls/gdiplus/matrix.c b/dlls/gdiplus/matrix.c
index d96f425aeef..fa287e6cb00 100644
--- a/dlls/gdiplus/matrix.c
+++ b/dlls/gdiplus/matrix.c
@@ -42,13 +42,15 @@ WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);
 static void matrix_multiply(GDIPCONST REAL * left, GDIPCONST REAL * right, REAL * out)
 {
     REAL temp[6];
-    int i, odd;
-
-    for(i = 0; i < 6; i++){
-        odd = i % 2;
-        temp[i] = left[i - odd] * right[odd] + left[i - odd + 1] * right[odd + 2] +
-                  (i >= 4 ? right[odd + 4] : 0.0);
-    }
+    // Unroll loop to optimize execution speed
+    temp[0] = left[0] * right[0] + left[1] * right[2];
+    temp[1] = left[0] * right[1] + left[1] * right[3];
+    temp[2] = left[2] * right[0] + left[3] * right[2];
+    temp[3] = left[2] * right[1] + left[3] * right[3];
+    temp[4] = left[4] * right[0] + left[5] * right[2] +
+                right[4];
+    temp[5] = left[4] * right[1] + left[5] * right[3] +
+                right[5];

memcpy(out, temp, 6 * sizeof(REAL));
 }