[flang-commits] [PATCH] D154072: [flang] Support CHARACTER(4) pointer targets

[Jean Perier via Phabricator via flang-commits]

jeanPerier created this revision.
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fir.rebox is emitting an llvm.sdiv to compute the character length
given the byte size from the input descriptor.
Inside a fir.global, this is not needed given the target length must
be accessible via the type, and it caused MLIR to fail LLVM IR
code generation (and crash).

Use the input type length when available instead.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154072

Files:
  flang/lib/Optimizer/CodeGen/CodeGen.cpp
  flang/test/Fir/rebox-global.fir


Index: flang/test/Fir/rebox-global.fir
===================================================================
--- flang/test/Fir/rebox-global.fir
+++ flang/test/Fir/rebox-global.fir
@@ -10,3 +10,14 @@
   fir.has_value %2 : !fir.box<!fir.ptr<i32>>
 }
 // CHECK: @p = global { ptr, i64, i32, i8, i8, i8, i8 } { ptr @x, {{.*}}, i32 {{.*}}, i8 0, i8 9, i8 1, i8 0 }
+
+// Test that sdiv is not generated inside fir.global.
+fir.global @char4 target : !fir.char<4,10>
+fir.global @pointer_char4_init : !fir.box<!fir.ptr<!fir.char<4,10>>> {
+  %0 = fir.address_of(@char4) : !fir.ref<!fir.char<4,10>>
+  %1 = fir.embox %0 : (!fir.ref<!fir.char<4,10>>) -> !fir.box<!fir.char<4,10>>
+  %2 = fircg.ext_rebox %1 : (!fir.box<!fir.char<4,10>>) -> !fir.box<!fir.ptr<!fir.char<4,10>>>
+  fir.has_value %2 : !fir.box<!fir.ptr<!fir.char<4,10>>>
+}
+// CHECK-LABEL: @pointer_char4_init
+// CHECK-SAME: { ptr @char4, i64 ptrtoint (ptr getelementptr ([10 x i32], ptr null, i32 1) to i64), i32 20180515, i8 0, i8 44, i8 1, i8 0 }
Index: flang/lib/Optimizer/CodeGen/CodeGen.cpp
===================================================================
--- flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -1894,14 +1894,22 @@
     llvm::SmallVector<mlir::Value, 2> lenParams;
     mlir::Type inputEleTy = getInputEleTy(rebox);
     if (auto charTy = inputEleTy.dyn_cast<fir::CharacterType>()) {
-      mlir::Value len = getElementSizeFromBox(
-          loc, idxTy, rebox.getBox().getType(), loweredBox, rewriter);
-      if (charTy.getFKind() != 1) {
-        mlir::Value width =
-            genConstantIndex(loc, idxTy, rewriter, charTy.getFKind());
-        len = rewriter.create<mlir::LLVM::SDivOp>(loc, idxTy, len, width);
+      if (charTy.hasConstantLen()) {
+        mlir::Value len =
+            genConstantIndex(loc, idxTy, rewriter, charTy.getLen());
+        lenParams.emplace_back(len);
+      } else {
+        mlir::Value len = getElementSizeFromBox(
+            loc, idxTy, rebox.getBox().getType(), loweredBox, rewriter);
+        if (charTy.getFKind() != 1) {
+          assert(!isInGlobalOp(rewriter) &&
+                 "character target in global op must have constant length");
+          mlir::Value width =
+              genConstantIndex(loc, idxTy, rewriter, charTy.getFKind());
+          len = rewriter.create<mlir::LLVM::SDivOp>(loc, idxTy, len, width);
+        }
+        lenParams.emplace_back(len);
       }
-      lenParams.emplace_back(len);
     } else if (auto recTy = inputEleTy.dyn_cast<fir::RecordType>()) {
       if (recTy.getNumLenParams() != 0)
         TODO(loc, "reboxing descriptor of derived type with length parameters");


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