[flang-commits] [flang] c164e63 - [flang][fir] Add conversion of `fir.iterate_while` to `scf.while`. (#152439)

via flang-commits flang-commits at lists.llvm.org
Wed Aug 13 22:39:59 PDT 2025


Author: Terapines MLIR
Date: 2025-08-14T13:39:55+08:00
New Revision: c164e6309b5bf5f6a8149df3df002bd327cf0748

URL: https://github.com/llvm/llvm-project/commit/c164e6309b5bf5f6a8149df3df002bd327cf0748
DIFF: https://github.com/llvm/llvm-project/commit/c164e6309b5bf5f6a8149df3df002bd327cf0748.diff

LOG: [flang][fir] Add conversion of `fir.iterate_while` to `scf.while`. (#152439)

This commmit is a supplement for
https://github.com/llvm/llvm-project/pull/140374.

RFC:https://discourse.llvm.org/t/rfc-add-fir-affine-optimization-fir-pass-pipeline/86190/6

Added: 
    flang/test/Fir/FirToSCF/iter-while.fir

Modified: 
    flang/lib/Optimizer/Transforms/FIRToSCF.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Optimizer/Transforms/FIRToSCF.cpp b/flang/lib/Optimizer/Transforms/FIRToSCF.cpp
index 79ed85fa60607..2bca0d98ec68d 100644
--- a/flang/lib/Optimizer/Transforms/FIRToSCF.cpp
+++ b/flang/lib/Optimizer/Transforms/FIRToSCF.cpp
@@ -36,7 +36,7 @@ struct DoLoopConversion : public mlir::OpRewritePattern<fir::DoLoopOp> {
     mlir::Value high = doLoopOp.getUpperBound();
     assert(low && high && "must be a Value");
     mlir::Value step = doLoopOp.getStep();
-    llvm::SmallVector<mlir::Value> iterArgs;
+    mlir::SmallVector<mlir::Value> iterArgs;
     if (hasFinalValue)
       iterArgs.push_back(low);
     iterArgs.append(doLoopOp.getIterOperands().begin(),
@@ -88,6 +88,73 @@ struct DoLoopConversion : public mlir::OpRewritePattern<fir::DoLoopOp> {
   }
 };
 
+struct IterWhileConversion : public mlir::OpRewritePattern<fir::IterWhileOp> {
+  using OpRewritePattern<fir::IterWhileOp>::OpRewritePattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(fir::IterWhileOp iterWhileOp,
+                  mlir::PatternRewriter &rewriter) const override {
+
+    mlir::Location loc = iterWhileOp.getLoc();
+    mlir::Value lowerBound = iterWhileOp.getLowerBound();
+    mlir::Value upperBound = iterWhileOp.getUpperBound();
+    mlir::Value step = iterWhileOp.getStep();
+
+    mlir::Value okInit = iterWhileOp.getIterateIn();
+    mlir::ValueRange iterArgs = iterWhileOp.getInitArgs();
+
+    mlir::SmallVector<mlir::Value> initVals;
+    initVals.push_back(lowerBound);
+    initVals.push_back(okInit);
+    initVals.append(iterArgs.begin(), iterArgs.end());
+
+    mlir::SmallVector<mlir::Type> loopTypes;
+    loopTypes.push_back(lowerBound.getType());
+    loopTypes.push_back(okInit.getType());
+    for (auto val : iterArgs)
+      loopTypes.push_back(val.getType());
+
+    auto scfWhileOp =
+        mlir::scf::WhileOp::create(rewriter, loc, loopTypes, initVals);
+
+    auto &beforeBlock = *rewriter.createBlock(
+        &scfWhileOp.getBefore(), scfWhileOp.getBefore().end(), loopTypes,
+        mlir::SmallVector<mlir::Location>(loopTypes.size(), loc));
+
+    mlir::Region::BlockArgListType argsInBefore =
+        scfWhileOp.getBefore().getArguments();
+    auto ivInBefore = argsInBefore[0];
+    auto earlyExitInBefore = argsInBefore[1];
+
+    rewriter.setInsertionPointToStart(&beforeBlock);
+
+    mlir::Value inductionCmp = mlir::arith::CmpIOp::create(
+        rewriter, loc, mlir::arith::CmpIPredicate::sle, ivInBefore, upperBound);
+    mlir::Value cond = mlir::arith::AndIOp::create(rewriter, loc, inductionCmp,
+                                                   earlyExitInBefore);
+
+    mlir::scf::ConditionOp::create(rewriter, loc, cond, argsInBefore);
+
+    rewriter.moveBlockBefore(iterWhileOp.getBody(), &scfWhileOp.getAfter(),
+                             scfWhileOp.getAfter().begin());
+
+    auto *afterBody = scfWhileOp.getAfterBody();
+    auto resultOp = mlir::cast<fir::ResultOp>(afterBody->getTerminator());
+    mlir::SmallVector<mlir::Value> results(resultOp->getOperands());
+    mlir::Value ivInAfter = scfWhileOp.getAfterArguments()[0];
+
+    rewriter.setInsertionPointToStart(afterBody);
+    results[0] = mlir::arith::AddIOp::create(rewriter, loc, ivInAfter, step);
+
+    rewriter.setInsertionPointToEnd(afterBody);
+    rewriter.replaceOpWithNewOp<mlir::scf::YieldOp>(resultOp, results);
+
+    scfWhileOp->setAttrs(iterWhileOp->getAttrs());
+    rewriter.replaceOp(iterWhileOp, scfWhileOp);
+    return mlir::success();
+  }
+};
+
 void copyBlockAndTransformResult(mlir::PatternRewriter &rewriter,
                                  mlir::Block &srcBlock, mlir::Block &dstBlock) {
   mlir::Operation *srcTerminator = srcBlock.getTerminator();
@@ -132,9 +199,10 @@ struct IfConversion : public mlir::OpRewritePattern<fir::IfOp> {
 
 void FIRToSCFPass::runOnOperation() {
   mlir::RewritePatternSet patterns(&getContext());
-  patterns.add<DoLoopConversion, IfConversion>(patterns.getContext());
+  patterns.add<DoLoopConversion, IterWhileConversion, IfConversion>(
+      patterns.getContext());
   mlir::ConversionTarget target(getContext());
-  target.addIllegalOp<fir::DoLoopOp, fir::IfOp>();
+  target.addIllegalOp<fir::DoLoopOp, fir::IterWhileOp, fir::IfOp>();
   target.markUnknownOpDynamicallyLegal([](mlir::Operation *) { return true; });
   if (failed(
           applyPartialConversion(getOperation(), target, std::move(patterns))))

diff  --git a/flang/test/Fir/FirToSCF/iter-while.fir b/flang/test/Fir/FirToSCF/iter-while.fir
new file mode 100644
index 0000000000000..0de7aabed120e
--- /dev/null
+++ b/flang/test/Fir/FirToSCF/iter-while.fir
@@ -0,0 +1,99 @@
+// RUN: fir-opt %s --fir-to-scf | FileCheck %s
+
+// CHECK-LABEL:   func.func @test_simple_iterate_while_1() -> (index, i1, i16, i32) {
+// CHECK:           %[[VAL_0:.*]] = arith.constant 11 : index
+// CHECK:           %[[VAL_1:.*]] = arith.constant 22 : index
+// CHECK:           %[[VAL_2:.*]] = arith.constant 2 : index
+// CHECK:           %[[VAL_3:.*]] = arith.constant true
+// CHECK:           %[[VAL_4:.*]] = arith.constant 123 : i16
+// CHECK:           %[[VAL_5:.*]] = arith.constant 456 : i32
+// CHECK:           %[[VAL_6:.*]]:4 = scf.while (%[[VAL_7:.*]] = %[[VAL_0]], %[[VAL_8:.*]] = %[[VAL_3]], %[[VAL_9:.*]] = %[[VAL_4]], %[[VAL_10:.*]] = %[[VAL_5]]) : (index, i1, i16, i32) -> (index, i1, i16, i32) {
+// CHECK:             %[[VAL_11:.*]] = arith.cmpi sle, %[[VAL_7]], %[[VAL_1]] : index
+// CHECK:             %[[VAL_12:.*]] = arith.andi %[[VAL_11]], %[[VAL_8]] : i1
+// CHECK:             scf.condition(%[[VAL_12]]) %[[VAL_7]], %[[VAL_8]], %[[VAL_9]], %[[VAL_10]] : index, i1, i16, i32
+// CHECK:           } do {
+// CHECK:           ^bb0(%[[VAL_13:.*]]: index, %[[VAL_14:.*]]: i1, %[[VAL_15:.*]]: i16, %[[VAL_16:.*]]: i32):
+// CHECK:             %[[VAL_17:.*]] = arith.addi %[[VAL_13]], %[[VAL_2]] : index
+// CHECK:             %[[VAL_18:.*]] = arith.constant true
+// CHECK:             %[[VAL_19:.*]] = arith.constant 22 : i16
+// CHECK:             %[[VAL_20:.*]] = arith.constant 33 : i32
+// CHECK:             scf.yield %[[VAL_17]], %[[VAL_18]], %[[VAL_19]], %[[VAL_20]] : index, i1, i16, i32
+// CHECK:           }
+// CHECK:           return %[[VAL_21:.*]]#0, %[[VAL_21]]#1, %[[VAL_21]]#2, %[[VAL_21]]#3 : index, i1, i16, i32
+// CHECK:         }
+func.func @test_simple_iterate_while_1() -> (index, i1, i16, i32) {
+  %lo = arith.constant 11 : index
+  %up = arith.constant 22 : index
+  %step = arith.constant 2 : index
+  %ok = arith.constant 1 : i1
+  %val1 = arith.constant 123 : i16
+  %val2 = arith.constant 456 : i32
+
+  %res:4 = fir.iterate_while (%i = %lo to %up step %step) and (%c = %ok) iter_args(%v1 = %val1, %v2 = %val2) -> (index, i1, i16, i32) {
+    %new_c = arith.constant 1 : i1
+    %new_v1 = arith.constant 22 : i16
+    %new_v2 = arith.constant 33 : i32
+    fir.result %i, %new_c, %new_v1, %new_v2 : index, i1, i16, i32
+  }
+
+  return %res#0, %res#1, %res#2, %res#3 : index, i1, i16, i32
+}
+
+// CHECK-LABEL:   func.func @test_simple_iterate_while_2(
+// CHECK-SAME:        %[[ARG0:.*]]: index, %[[ARG1:.*]]: index, %[[ARG2:.*]]: i1, %[[ARG3:.*]]: i32) -> (index, i1, i32) {
+// CHECK:           %[[VAL_0:.*]] = arith.constant 1 : index
+// CHECK:           %[[VAL_1:.*]]:3 = scf.while (%[[VAL_2:.*]] = %[[ARG0]], %[[VAL_3:.*]] = %[[ARG2]], %[[VAL_4:.*]] = %[[ARG3]]) : (index, i1, i32) -> (index, i1, i32) {
+// CHECK:             %[[VAL_5:.*]] = arith.cmpi sle, %[[VAL_2]], %[[ARG1]] : index
+// CHECK:             %[[VAL_6:.*]] = arith.andi %[[VAL_5]], %[[VAL_3]] : i1
+// CHECK:             scf.condition(%[[VAL_6]]) %[[VAL_2]], %[[VAL_3]], %[[VAL_4]] : index, i1, i32
+// CHECK:           } do {
+// CHECK:           ^bb0(%[[VAL_7:.*]]: index, %[[VAL_8:.*]]: i1, %[[VAL_9:.*]]: i32):
+// CHECK:             %[[VAL_10:.*]] = arith.addi %[[VAL_7]], %[[VAL_0]] : index
+// CHECK:             %[[VAL_11:.*]] = arith.constant 123 : i32
+// CHECK:             %[[VAL_12:.*]] = arith.constant true
+// CHECK:             scf.yield %[[VAL_10]], %[[VAL_12]], %[[VAL_11]] : index, i1, i32
+// CHECK:           }
+// CHECK:           return %[[VAL_13:.*]]#0, %[[VAL_13]]#1, %[[VAL_13]]#2 : index, i1, i32
+// CHECK:         }
+func.func @test_simple_iterate_while_2(%start: index, %stop: index, %cond: i1, %val: i32) -> (index, i1, i32) {
+  %step = arith.constant 1 : index
+
+  %res:3 = fir.iterate_while (%i = %start to %stop step %step) and (%ok = %cond) iter_args(%x = %val) -> (index, i1, i32) {
+    %new_x = arith.constant 123 : i32
+    %new_ok = arith.constant 1 : i1
+    fir.result %i, %new_ok, %new_x : index, i1, i32
+  }
+
+  return %res#0, %res#1, %res#2 : index, i1, i32
+}
+
+// CHECK-LABEL:   func.func @test_zero_iterations() -> (index, i1, i8) {
+// CHECK:           %[[VAL_0:.*]] = arith.constant 10 : index
+// CHECK:           %[[VAL_1:.*]] = arith.constant 5 : index
+// CHECK:           %[[VAL_2:.*]] = arith.constant 1 : index
+// CHECK:           %[[VAL_3:.*]] = arith.constant true
+// CHECK:           %[[VAL_4:.*]] = arith.constant 42 : i8
+// CHECK:           %[[VAL_5:.*]]:3 = scf.while (%[[VAL_6:.*]] = %[[VAL_0]], %[[VAL_7:.*]] = %[[VAL_3]], %[[VAL_8:.*]] = %[[VAL_4]]) : (index, i1, i8) -> (index, i1, i8) {
+// CHECK:             %[[VAL_9:.*]] = arith.cmpi sle, %[[VAL_6]], %[[VAL_1]] : index
+// CHECK:             %[[VAL_10:.*]] = arith.andi %[[VAL_9]], %[[VAL_7]] : i1
+// CHECK:             scf.condition(%[[VAL_10]]) %[[VAL_6]], %[[VAL_7]], %[[VAL_8]] : index, i1, i8
+// CHECK:           } do {
+// CHECK:           ^bb0(%[[VAL_11:.*]]: index, %[[VAL_12:.*]]: i1, %[[VAL_13:.*]]: i8):
+// CHECK:             %[[VAL_14:.*]] = arith.addi %[[VAL_11]], %[[VAL_2]] : index
+// CHECK:             scf.yield %[[VAL_14]], %[[VAL_12]], %[[VAL_13]] : index, i1, i8
+// CHECK:           }
+// CHECK:           return %[[VAL_15:.*]]#0, %[[VAL_15]]#1, %[[VAL_15]]#2 : index, i1, i8
+// CHECK:         }
+func.func @test_zero_iterations() -> (index, i1, i8) {
+  %lo = arith.constant 10 : index
+  %up = arith.constant 5 : index
+  %step = arith.constant 1 : index
+  %ok = arith.constant 1 : i1
+  %x = arith.constant 42 : i8
+
+  %res:3 = fir.iterate_while (%i = %lo to %up step %step) and (%c = %ok) iter_args(%xv = %x) -> (index, i1, i8) {
+    fir.result %i, %c, %xv : index, i1, i8
+  }
+
+  return %res#0, %res#1, %res#2 : index, i1, i8
+}


        


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