Fix a bug in the calculation of stack uniformity

alan-baker · alan-baker · commit d7ea45d279c1 · 2023-09-07T20:28:54.000-04:00
* The simulation incorrectly marked some continues as non-uniform
  * this leads to some ballots being marked with the special value
  * in WGSLv1, Workgroup, and Subgroup styles this would lead to fewer
    ballots being checked (so likely no change in results)
  * in Maximal though, this leads to some ballots being a wacky value
    and extra failures
diff --git a/src/webgpu/shader/execution/reconvergence/util.ts b/src/webgpu/shader/execution/reconvergence/util.ts
@@ -1966,7 +1966,7 @@ ${this.functions[i]}`;
             break;
           }
 
-          const uniform = this.style === Style.WGSLv1 && this.isUniform(mask, subgroupSize);
+          const uniform = this.style !== Style.WGSLv1 || this.isUniform(mask, subgroupSize);
 
           let n = nesting;
           for (; n >= 0; n--) {

Original file line number	Diff line number	Diff line change
@@ -1966,7 +1966,7 @@ ${this.functions[i]}`;
`1966`	`1966`	`break;`
`1967`	`1967`	`}`
`1968`	`1968`
`1969`		`- const uniform = this.style === Style.WGSLv1 && this.isUniform(mask, subgroupSize);`
	`1969`	`+ const uniform = this.style !== Style.WGSLv1 \|\| this.isUniform(mask, subgroupSize);`
`1970`	`1970`
`1971`	`1971`	`let n = nesting;`
`1972`	`1972`	`for (; n >= 0; n--) {`