Fix reconvergence test to be agnostic to wave size

Author: luciechoi

test/Feature/MaximalReconvergence/subgroup_uniform_control_flow.test

@@ -1,22 +1,31 @@
 #--- source.hlsl
-RWStructuredBuffer<uint> Out : register(u0);
+RWStructuredBuffer<float> Out : register(u0);
 
 [numthreads(8,1,1)]
 void main(uint3 TID : SV_GroupThreadID) {
+    float maxActiveLaneCount = min(WaveGetLaneCount(), 8);
+    float div1 = 1.0/maxActiveLaneCount;
+    float div2 = 2.0/maxActiveLaneCount;
+    float div4 = 4.0/maxActiveLaneCount;
+    float div8 = 8.0/maxActiveLaneCount;
+
+    float result = 0;
+
     // First non-uniform branch
-    if (TID.x < 4) {
+    if (TID.x % 2 == 0) {
         // Second non-uniform branch
-        if (TID.x % 2 == 0) {
-            Out[TID.x] = WaveActiveSum(TID.x);
+        if (TID.x % 4 == 0) {
+            result += WaveActiveSum(div4);
         } else {
-            Out[TID.x] = WaveActiveMax(TID.x);
+            result += WaveActiveSum(div8);
         }
         // Must reconverge here with maximal reconvergence
-        Out[TID.x] += WaveActiveMax(TID.x);
-    } else {
-        Out[4] = WaveActiveMax(TID.x);
+        result += WaveActiveSum(div2);
     }
-    Out[TID.x] += WaveActiveMax(TID.x);
+
+    // Must reconverge here with maximal reconvergence
+    result += WaveActiveSum(div1);
+    Out[TID.x] = result;
 }
 
 //--- pipeline.yaml
@@ -28,7 +37,7 @@ Shaders:
     DispatchSize: [1, 1, 1]
 Buffers:
   - Name: Out
-    Format: UInt32
+    Format: Float32
     Data: [ 0, 0, 0, 0, 0, 0, 0, 0 ]
 DescriptorSets:
   - Resources:
@@ -44,16 +53,16 @@ DescriptorSets:
 #--- end
 # UNSUPPORTED: Vulkan && !VK_KHR_shader_maximal_reconvergence
 
-# BUG: https://github.com/llvm/offload-test-suite/issues/490
-# XFAIL: WARP && DirectX
-
 # BUG: https://github.com/llvm/llvm-project/issues/165288
 # XFAIL: !WARP && Clang && (DirectX || Metal)
 
+# BUG: https://github.com/llvm/llvm-project/issues/99159
+# XFAIL: Clang
+
 # RUN: split-file %s %t
 # RUN: %dxc_target -T cs_6_0 -fspv-enable-maximal-reconvergence -Fo %t.o %t/source.hlsl
 # RUN: %offloader %t/pipeline.yaml %t.o | FileCheck %s
 
 # CHECK: Name: Out
-# CHECK: Format: UInt32
-# CHECK: Data: [ 12, 13, 12, 13, 14, 7, 7, 7 ]
+# CHECK: Format: Float32
+# CHECK: Data: [ 3, 1, 4, 1, 3, 1, 4, 1 ]