[flang-commits] [flang] [flang][Transforms] Add LiftSCFWhileToSCFFor pass (PR #213273)

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``````````bash
git-clang-format --diff origin/main HEAD --extensions cpp -- flang/lib/Optimizer/Transforms/LiftSCFWhileToSCFFor.cpp --diff_from_common_commit
``````````

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``````````diff
diff --git a/flang/lib/Optimizer/Transforms/LiftSCFWhileToSCFFor.cpp b/flang/lib/Optimizer/Transforms/LiftSCFWhileToSCFFor.cpp
index 0978e8ae8..920909d92 100644
--- a/flang/lib/Optimizer/Transforms/LiftSCFWhileToSCFFor.cpp
+++ b/flang/lib/Optimizer/Transforms/LiftSCFWhileToSCFFor.cpp
@@ -117,8 +117,8 @@ struct AffineRecurrence {
 // loop-invariant w.r.t. `whileOp`), return the recurrence op, the step value,
 // and whether the recurrence is a subtraction. The returned step is the raw
 // RHS; for arith.subi the caller should interpret it as a negative step.
-static AffineRecurrence matchAffineRecurrence(
-    Value v, Value beforeArg, scf::WhileOp whileOp) {
+static AffineRecurrence matchAffineRecurrence(Value v, Value beforeArg,
+                                              scf::WhileOp whileOp) {
   if (auto add = v.getDefiningOp<arith::AddIOp>()) {
     if (add.getLhs() == beforeArg && isLoopInvariant(add.getRhs(), whileOp)) {
       return {add.getOperation(), add.getRhs(), /*isSub=*/false};
@@ -218,8 +218,7 @@ struct LoopInfo {
 
   LoopInfo(scf::WhileOp whileOp, Block *continuesBlock, Value tripInit,
            Operation *tripRecurrence, unsigned ivArgIdx, Value ivInit,
-           Value ivStep, Operation *ivRecurrence,
-           SmallVector<IterArg> iterArgs)
+           Value ivStep, Operation *ivRecurrence, SmallVector<IterArg> iterArgs)
       : whileOp(whileOp), continuesBlock(continuesBlock), tripInit(tripInit),
         tripRecurrence(tripRecurrence), ivArgIdx(ivArgIdx), ivInit(ivInit),
         ivStep(ivStep), ivRecurrence(ivRecurrence),
@@ -228,8 +227,8 @@ struct LoopInfo {
 
 // Try to build a LoopInfo for `whileOp`. On failure, emit a one-line stderr
 // diagnostic explaining why and return std::nullopt.
-static std::optional<LoopInfo> tryBuildLoopInfo(
-    scf::WhileOp whileOp, llvm::raw_ostream &os) {
+static std::optional<LoopInfo> tryBuildLoopInfo(scf::WhileOp whileOp,
+                                                llvm::raw_ostream &os) {
   auto bail = [&](StringRef reason) -> std::optional<LoopInfo> {
     os << "  [skip] " << reason << "\n";
     return std::nullopt;
@@ -289,7 +288,7 @@ static std::optional<LoopInfo> tryBuildLoopInfo(
   auto contYield = cast<scf::YieldOp>(cont->getTerminator());
 
   for (auto [argIdx, beforeArg] :
-      llvm::enumerate(whileOp.getBeforeArguments())) {
+       llvm::enumerate(whileOp.getBeforeArguments())) {
     Value nextInBefore = getNextIterValueInBefore(whileOp, (unsigned)argIdx);
 
     // In the canonical lift-cf-to-scf shape every iteration value flows
@@ -420,10 +419,11 @@ static void rewriteToSCFFor(const LoopInfo &info, llvm::raw_ostream &os) {
   //   ub     = arith.addi ivInit, scaled
   IntegerAttr ivStepAttr;
   bool ivStepIsOne = matchPattern(info.ivStep, m_Constant(&ivStepAttr)) &&
-      ivStepAttr.getInt() == 1;
-  Value scaled = ivStepIsOne
-      ? info.tripInit
-      : arith::MulIOp::create(builder, loc, info.tripInit, info.ivStep);
+                     ivStepAttr.getInt() == 1;
+  Value scaled =
+      ivStepIsOne
+          ? info.tripInit
+          : arith::MulIOp::create(builder, loc, info.tripInit, info.ivStep);
   Value ub = arith::AddIOp::create(builder, loc, info.ivInit, scaled);
 
   Value lbIdx = castTo(info.ivInit, indexType);

``````````

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https://github.com/llvm/llvm-project/pull/213273