commit a159128811ae1d0a781dbc8590fa1e0f26642f82
author Diana Picus <diana.picus@linaro.org> Tue May 31 10:55:56 2022 +0000
committer Diana Picus <diana.picus@linaro.org> Wed Jun 01 08:00:45 2022 +0000
tree 2f4d98e9052dbd9d1b3291ed98d1a3b32fc0715e
parent d597a461e0f5b1d7508983878bc5a38326cffd14

[flang] Upstream lowering of real control loops

Upstream the code for handling loops with real control variables from
the fir-dev branch at
https://github.com/flang-compiler/f18-llvm-project/tree/fir-dev/

Also add a test.

Loops with real-valued control variables are always lowered to
unstructured loops. The real-valued control variables are handled the
same as integer ones, the only difference is that they need to use
floating point instructions instead of the integer equivalents.

Co-authored-by: V Donaldson <vdonaldson@nvidia.com>

flang/lib/Lower/Bridge.cpp

diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index a33ddee..bbce38e 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -95,6 +95,7 @@
   fir::DoLoopOp doLoop = nullptr;
 
   // Data members for unstructured loops.
+  bool hasRealControl = false;
   mlir::Value tripVariable = nullptr;
   mlir::Block *headerBlock = nullptr; // loop entry and test block
   mlir::Block *bodyBlock = nullptr;   // first loop body block
@@ -997,6 +998,8 @@
           bounds->step);
       if (unstructuredContext) {
         maybeStartBlock(preheaderBlock);
+        info.hasRealControl = info.loopVariableSym.GetType()->IsNumeric(
+            Fortran::common::TypeCategory::Real);
         info.headerBlock = headerBlock;
         info.bodyBlock = bodyBlock;
         info.exitBlock = exitBlock;
@@ -1034,6 +1037,9 @@
       if (expr)
         return builder->createConvert(loc, controlType,
                                       createFIRExpr(loc, expr, stmtCtx));
+
+      if (info.hasRealControl)
+        return builder->createRealConstant(loc, controlType, 1u);
       return builder->createIntegerConstant(loc, controlType, 1); // step
     };
     for (IncrementLoopInfo &info : incrementLoopNestInfo) {
@@ -1059,12 +1065,24 @@
 
       // Unstructured loop preheader - initialize tripVariable and loopVariable.
       mlir::Value tripCount;
-      auto diff1 =
-          builder->create<mlir::arith::SubIOp>(loc, upperValue, lowerValue);
-      auto diff2 =
-          builder->create<mlir::arith::AddIOp>(loc, diff1, info.stepValue);
-      tripCount =
-          builder->create<mlir::arith::DivSIOp>(loc, diff2, info.stepValue);
+      if (info.hasRealControl) {
+        auto diff1 =
+            builder->create<mlir::arith::SubFOp>(loc, upperValue, lowerValue);
+        auto diff2 =
+            builder->create<mlir::arith::AddFOp>(loc, diff1, info.stepValue);
+        tripCount =
+            builder->create<mlir::arith::DivFOp>(loc, diff2, info.stepValue);
+        tripCount =
+            builder->createConvert(loc, builder->getIndexType(), tripCount);
+
+      } else {
+        auto diff1 =
+            builder->create<mlir::arith::SubIOp>(loc, upperValue, lowerValue);
+        auto diff2 =
+            builder->create<mlir::arith::AddIOp>(loc, diff1, info.stepValue);
+        tripCount =
+            builder->create<mlir::arith::DivSIOp>(loc, diff2, info.stepValue);
+      }
       info.tripVariable = builder->createTemporary(loc, tripCount.getType());
       builder->create<fir::StoreOp>(loc, tripCount, info.tripVariable);
       builder->create<fir::StoreOp>(loc, lowerValue, info.loopVariable);
@@ -1117,7 +1135,12 @@
       tripCount = builder->create<mlir::arith::SubIOp>(loc, tripCount, one);
       builder->create<fir::StoreOp>(loc, tripCount, info.tripVariable);
       mlir::Value value = builder->create<fir::LoadOp>(loc, info.loopVariable);
-      value = builder->create<mlir::arith::AddIOp>(loc, value, info.stepValue);
+      if (info.hasRealControl)
+        value =
+            builder->create<mlir::arith::AddFOp>(loc, value, info.stepValue);
+      else
+        value =
+            builder->create<mlir::arith::AddIOp>(loc, value, info.stepValue);
       builder->create<fir::StoreOp>(loc, value, info.loopVariable);
 
       genFIRBranch(info.headerBlock);