differgence in OpenCL code

remove branch differgences in AMD OpenCl code based on #454

a Please enter the commit message for your changes. Lines starting

xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl

@@ -653,21 +653,11 @@ __kernel void cn2(__global uint4 *Scratchpad, __global ulong *states, __global u
 
 			for(int i = 0; i < 25; ++i) states[i] = State[i];
 
-			switch(State[0] & 3)
-			{
-				case 0:
-					Branch0[atomic_inc(Branch0 + Threads)] = get_global_id(0) - get_global_offset(0);
-					break;
-				case 1:
-					Branch1[atomic_inc(Branch1 + Threads)] = get_global_id(0) - get_global_offset(0);
-					break;
-				case 2:
-					Branch2[atomic_inc(Branch2 + Threads)] = get_global_id(0) - get_global_offset(0);
-					break;
-				case 3:
-					Branch3[atomic_inc(Branch3 + Threads)] = get_global_id(0) - get_global_offset(0);
-					break;
-			}
+			ulong StateSwitch = State[0] & 3;
+			__global uint *destinationBranch1 = StateSwitch == 0 ? Branch0 : Branch1;
+			__global uint *destinationBranch2 = StateSwitch == 2 ? Branch2 : Branch3;
+			__global uint *destinationBranch = StateSwitch < 2 ? destinationBranch1 : destinationBranch2;
+			destinationBranch[atomic_inc(destinationBranch + Threads)] = gIdx;
 		}
 	}
 	mem_fence(CLK_GLOBAL_MEM_FENCE);
@@ -704,8 +694,7 @@ __kernel void Skein(__global ulong *states, __global uint *BranchBuf, __global u
 
 		for(uint i = 0; i < 4; ++i)
 		{
-			if(i < 3) t[0] += 0x40UL;
-			else t[0] += 0x08UL;
+			t[0] += i < 3 ? 0x40UL : 0x08UL;
 
 			t[2] = t[0] ^ t[1];
 
@@ -715,8 +704,7 @@ __kernel void Skein(__global ulong *states, __global uint *BranchBuf, __global u
 
 			h = m ^ p;
 
-			if(i < 2) t[1] = 0x3000000000000000UL;
-			else t[1] = 0xB000000000000000UL;
+			t[1] = i < 2 ? 0x3000000000000000UL : 0xB000000000000000UL;
 		}
 
 		t[0] = 0x08UL;
@@ -744,6 +732,27 @@ __kernel void Skein(__global ulong *states, __global uint *BranchBuf, __global u
 
 #define SWAP8(x)	as_ulong(as_uchar8(x).s76543210)
 
+#define JHXOR \
+	h0h ^= input[0]; \
+	h0l ^= input[1]; \
+	h1h ^= input[2]; \
+	h1l ^= input[3]; \
+	h2h ^= input[4]; \
+	h2l ^= input[5]; \
+	h3h ^= input[6]; \
+	h3l ^= input[7]; \
+\
+	E8; \
+\
+	h4h ^= input[0]; \
+	h4l ^= input[1]; \
+	h5h ^= input[2]; \
+	h5l ^= input[3]; \
+	h6h ^= input[4]; \
+	h6l ^= input[5]; \
+	h7h ^= input[6]; \
+	h7l ^= input[7]
+
 __kernel void JH(__global ulong *states, __global uint *BranchBuf, __global uint *output, ulong Target, ulong Threads)
 {
 	const uint idx = get_global_id(0) - get_global_offset(0);
@@ -757,46 +766,27 @@ __kernel void JH(__global ulong *states, __global uint *BranchBuf, __global uint
 		sph_u64 h4h = 0x754D2E7F8996A371UL, h4l = 0x62E27DF70849141DUL, h5h = 0x948F2476F7957627UL, h5l = 0x6C29804757B6D587UL, h6h = 0x6C0D8EAC2D275E5CUL, h6l = 0x0F7A0557C6508451UL, h7h = 0xEA12247067D3E47BUL, h7l = 0x69D71CD313ABE389UL;
 		sph_u64 tmp;
 
-		for(int i = 0; i < 5; ++i)
+		for(int i = 0; i < 3; ++i)
 		{
 			ulong input[8];
 
-			if(i < 3)
-			{
-				for(int x = 0; x < 8; ++x) input[x] = (states[(i << 3) + x]);
-			}
-			else if(i == 3)
-			{
-				input[0] = (states[24]);
-				input[1] = 0x80UL;
-				for(int x = 2; x < 8; ++x) input[x] = 0x00UL;
-			}
-			else
-			{
-				input[7] = 0x4006000000000000UL;
-
-				for(int x = 0; x < 7; ++x) input[x] = 0x00UL;
-			}
-
-			h0h ^= input[0];
-			h0l ^= input[1];
-			h1h ^= input[2];
-			h1l ^= input[3];
-			h2h ^= input[4];
-			h2l ^= input[5];
-			h3h ^= input[6];
-			h3l ^= input[7];
-
-			E8;
-
-			h4h ^= input[0];
-			h4l ^= input[1];
-			h5h ^= input[2];
-			h5l ^= input[3];
-			h6h ^= input[4];
-			h6l ^= input[5];
-			h7h ^= input[6];
-			h7l ^= input[7];
+			const int shifted = i << 3;
+			for(int x = 0; x < 8; ++x) input[x] = (states[shifted + x]);
+			JHXOR;
+		}
+		{
+			ulong input[8];
+			input[0] = (states[24]);
+			input[1] = 0x80UL;
+			#pragma unroll 6
+			for(int x = 2; x < 8; ++x) input[x] = 0x00UL;
+			JHXOR;
+		}
+		{
+			ulong input[8];
+			for(int x = 0; x < 7; ++x) input[x] = 0x00UL;
+			input[7] = 0x4006000000000000UL;
+			JHXOR;
 		}
 
 		//output[0] = h6h;
@@ -832,6 +822,7 @@ __kernel void Blake(__global ulong *states, __global uint *BranchBuf, __global u
 
 		((uint8 *)h)[0] = vload8(0U, c_IV256);
 
+		#pragma unroll 4
 		for(uint i = 0, bitlen = 0; i < 4; ++i)
 		{
 			if(i < 3)
@@ -907,6 +898,7 @@ __kernel void Groestl(__global ulong *states, __global uint *BranchBuf, __global
 
 		State[7] = 0x0001000000000000UL;
 
+		#pragma unroll 4
 		for(uint i = 0; i < 4; ++i)
 		{
 			ulong H[8], M[8];