[PATCH] D61037: [WebAssembly] Implement ReplaceNodeResults to fix a SIMD crash

[Thomas Lively via Phabricator via llvm-commits]

tlively created this revision.
tlively added a reviewer: aheejin.
Herald added subscribers: llvm-commits, sunfish, hiraditya, jgravelle-google, sbc100, dschuff.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D61037

Files:
  llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
  llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
  llvm/test/CodeGen/WebAssembly/simd-illegal-signext.ll


Index: llvm/test/CodeGen/WebAssembly/simd-illegal-signext.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/WebAssembly/simd-illegal-signext.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s -mattr=+simd128 | FileCheck %s
+
+; Regression test for a crash caused by
+; WebAssemblyTargetLowering::ReplaceNodeResults not being
+; implemented. Since SIMD is enabled, sign_ext_inreg is custom lowered
+; but the result is i16, an illegal value. This requires
+; ReplaceNodeResults to resolve, but the default implementation is to
+; abort.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-emscripten"
+
+; CHECK: i32.load8_s
+; CHECK-NEXT: i32.store16
+define void @foo() #0 {
+entry:
+  %0 = load i32*, i32** undef, align 4
+  %1 = load i32, i32* %0, align 4
+  %2 = load i32, i32* undef, align 4
+  %conv67 = trunc i32 %2 to i8
+  %conv68 = sext i8 %conv67 to i16
+  store i16 %conv68, i16* null, align 2
+  ret void
+}
Index: llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
+++ llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
@@ -85,6 +85,9 @@
                                const SDLoc &DL, SelectionDAG &DAG,
                                SmallVectorImpl<SDValue> &InVals) const override;
 
+  void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
+                          SelectionDAG &DAG) const override;
+
   // Custom lowering hooks.
   SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
   SDValue LowerFrameIndex(SDValue Op, SelectionDAG &DAG) const;
Index: llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
===================================================================
--- llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -885,6 +885,12 @@
   return Chain;
 }
 
+void WebAssemblyTargetLowering::ReplaceNodeResults(
+    SDNode *N, SmallVectorImpl<SDValue> &Results, SelectionDAG &DAG) const {
+  // Do not add any results, signifying that N should not be custom lowered
+  // after all
+}
+
 //===----------------------------------------------------------------------===//
 //  Custom lowering hooks.
 //===----------------------------------------------------------------------===//


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