[flang-commits] [flang] 32e0824 - [flang][CodeGen] Transform `fir.unreachable` to `llvm.unreachable`

[Andrzej Warzynski via flang-commits]

Author: Andrzej Warzynski
Date: 2021-11-02T18:22:51Z
New Revision: 32e08248aa113bf3a5008d580753876fe3bcf021

URL: https://github.com/llvm/llvm-project/commit/32e08248aa113bf3a5008d580753876fe3bcf021
DIFF: https://github.com/llvm/llvm-project/commit/32e08248aa113bf3a5008d580753876fe3bcf021.diff

LOG: [flang][CodeGen] Transform `fir.unreachable` to `llvm.unreachable`

This patch extends the `FIRToLLVMLowering` pass in Flang by adding a
hook to transform `fir.unreachable` to `llvm.unreachable`.

This is part of the upstreaming effort from the `fir-dev` branch in [1].

[1] https://github.com/flang-compiler/f18-llvm-project

Co-authored-by: Eric Schweitz <eschweitz at nvidia.com>

Differential Revision: https://reviews.llvm.org/D113023

Added: 
    

Modified: 
    flang/lib/Optimizer/CodeGen/CodeGen.cpp
    flang/test/Fir/convert-to-llvm.fir

Removed: 
    


################################################################################
diff  --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index ce4860c8c0c6..15ac2d7cb45f 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -167,6 +167,18 @@ struct UndefOpConversion : public FIROpConversion<fir::UndefOp> {
   }
 };
 
+// convert to LLVM IR dialect `unreachable`
+struct UnreachableOpConversion : public FIROpConversion<fir::UnreachableOp> {
+  using FIROpConversion::FIROpConversion;
+
+  mlir::LogicalResult
+  matchAndRewrite(fir::UnreachableOp unreach, OpAdaptor adaptor,
+                  mlir::ConversionPatternRewriter &rewriter) const override {
+    rewriter.replaceOpWithNewOp<mlir::LLVM::UnreachableOp>(unreach);
+    return success();
+  }
+};
+
 struct ZeroOpConversion : public FIROpConversion<fir::ZeroOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -190,6 +202,7 @@ struct ZeroOpConversion : public FIROpConversion<fir::ZeroOp> {
     return success();
   }
 };
+
 } // namespace
 
 namespace {
@@ -207,8 +220,10 @@ class FIRToLLVMLowering : public fir::FIRToLLVMLoweringBase<FIRToLLVMLowering> {
     auto *context = getModule().getContext();
     fir::LLVMTypeConverter typeConverter{getModule()};
     mlir::OwningRewritePatternList pattern(context);
-    pattern.insert<AddrOfOpConversion, HasValueOpConversion, GlobalOpConversion,
-                   UndefOpConversion, ZeroOpConversion>(typeConverter);
+    pattern
+        .insert<AddrOfOpConversion, HasValueOpConversion, GlobalOpConversion,
+                UndefOpConversion, UnreachableOpConversion, ZeroOpConversion>(
+            typeConverter);
     mlir::populateStdToLLVMConversionPatterns(typeConverter, pattern);
     mlir::arith::populateArithmeticToLLVMConversionPatterns(typeConverter,
                                                             pattern);

diff  --git a/flang/test/Fir/convert-to-llvm.fir b/flang/test/Fir/convert-to-llvm.fir
index a20037beeb8c..3ef31ac28818 100644
--- a/flang/test/Fir/convert-to-llvm.fir
+++ b/flang/test/Fir/convert-to-llvm.fir
@@ -133,3 +133,15 @@ func @zero_test_float() {
 // CHECK: %{{.*}} = llvm.mlir.constant(0.000000e+00 : f80) : f80
 // CHECK: %{{.*}} = llvm.mlir.constant(0.000000e+00 : f128) : f128
 // CHECK-NOT: fir.zero_bits
+
+// -----
+
+// Verify that fir.unreachable is transformed to llvm.unreachable
+
+// CHECK:  llvm.func @test_unreachable() {
+// CHECK-NEXT:    llvm.unreachable
+// CHECK-NEXT:  }
+
+func @test_unreachable() {
+  fir.unreachable
+}