[spirv-reader] Remove `forced` param from `MakeBranchDetailed`.

The `forced` parameter is always false, remove it.

Change-Id: I9aa16dfc6a51516f6b6e619a3c8ce982a25ba4c4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/111101
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>

src/tint/reader/spirv/function.cc

@@ -3261,11 +3261,8 @@ bool FunctionEmitter::EmitNormalTerminator(const BlockInfo& block_info) {
             // start of an if-selection or a switch-selection.  So at most one branch
             // is a kForward, kCaseFallThrough, or kIfBreak.
 
-            // The fallthrough case is special because WGSL requires the fallthrough
+            if (true_kind == EdgeKind::kCaseFallThrough ||
-            // statement to be last in the case clause.
+                false_kind == EdgeKind::kCaseFallThrough) {
-            if (true_kind == EdgeKind::kCaseFallThrough) {
-                return Fail() << "Fallthrough not supported in WGSL";
-            } else if (false_kind == EdgeKind::kCaseFallThrough) {
                 return Fail() << "Fallthrough not supported in WGSL";
             }
 
@@ -3278,8 +3275,8 @@ bool FunctionEmitter::EmitNormalTerminator(const BlockInfo& block_info) {
             // requiring a flow guard, then get that flow guard name too.  It will
             // come from at most one of these two branches.
             std::string flow_guard;
-            auto* true_branch = MakeBranchDetailed(block_info, *true_info, false, &flow_guard);
+            auto* true_branch = MakeBranchDetailed(block_info, *true_info, &flow_guard);
-            auto* false_branch = MakeBranchDetailed(block_info, *false_info, false, &flow_guard);
+            auto* false_branch = MakeBranchDetailed(block_info, *false_info, &flow_guard);
 
             AddStatement(MakeSimpleIf(cond, true_branch, false_branch));
             if (!flow_guard.empty()) {
@@ -3304,7 +3301,6 @@ bool FunctionEmitter::EmitNormalTerminator(const BlockInfo& block_info) {
 
 const ast::Statement* FunctionEmitter::MakeBranchDetailed(const BlockInfo& src_info,
                                                           const BlockInfo& dest_info,
-                                                          bool forced,
                                                           std::string* flow_guard_name_ptr) {
     auto kind = src_info.succ_edge.find(dest_info.id)->second;
     switch (kind) {
@@ -3312,11 +3308,7 @@ const ast::Statement* FunctionEmitter::MakeBranchDetailed(const BlockInfo& src_i
             // Nothing to do. The loop backedge is implicit.
             break;
         case EdgeKind::kSwitchBreak: {
-            if (forced) {
+            // Don't bother with a break at the end of a case/default clause.
-                return create<ast::BreakStatement>(Source{});
-            }
-            // Unless forced, don't bother with a break at the end of a case/default
-            // clause.
             const auto header = dest_info.header_for_merge;
             TINT_ASSERT(Reader, header != 0);
             const auto* exiting_construct = GetBlockInfo(header)->construct;

src/tint/reader/spirv/function.h

@@ -721,36 +721,22 @@ class FunctionEmitter {
     /// @param dest_info the destination block
     /// @returns the new statement, or a null statement
     const ast::Statement* MakeBranch(const BlockInfo& src_info, const BlockInfo& dest_info) {
-        return MakeBranchDetailed(src_info, dest_info, false, nullptr);
+        return MakeBranchDetailed(src_info, dest_info, nullptr);
     }
 
     /// Returns a new statement to represent the given branch representing a
     /// "normal" terminator, as in the sense of EmitNormalTerminator.  If no
-    /// WGSL statement is required, the statement will be nullptr.
+    /// WGSL statement is required, the statement will be nullptr. This method tries to avoid
-    /// @param src_info the source block
+    /// emitting a 'break' statement when that would be redundant in WGSL due to implicit breaking
-    /// @param dest_info the destination block
+    /// out of a switch. If the control flow edge is an if-break for an if-selection with a
-    /// @returns the new statement, or a null statement
-    const ast::Statement* MakeForcedBranch(const BlockInfo& src_info, const BlockInfo& dest_info) {
-        return MakeBranchDetailed(src_info, dest_info, true, nullptr);
-    }
-
-    /// Returns a new statement to represent the given branch representing a
-    /// "normal" terminator, as in the sense of EmitNormalTerminator.  If no
-    /// WGSL statement is required, the statement will be nullptr. When `forced`
-    /// is false, this method tries to avoid emitting a 'break' statement when
-    /// that would be redundant in WGSL due to implicit breaking out of a switch.
-    /// When `forced` is true, the method won't try to avoid emitting that break.
-    /// If the control flow edge is an if-break for an if-selection with a
     /// control flow guard, then return that guard name via `flow_guard_name_ptr`
     /// when that parameter is not null.
     /// @param src_info the source block
     /// @param dest_info the destination block
-    /// @param forced if true, always emit the branch (if it exists in WGSL)
     /// @param flow_guard_name_ptr return parameter for control flow guard name
     /// @returns the new statement, or a null statement
     const ast::Statement* MakeBranchDetailed(const BlockInfo& src_info,
                                              const BlockInfo& dest_info,
-                                             bool forced,
                                              std::string* flow_guard_name_ptr);
 
     /// Returns a new if statement with the given statements as the then-clause