[WebAssembly] Implement isCheapToSpeculateCtlz and isCheapToSpeculateCttz.

This unbreaks test/CodeGen/WebAssembly/i32.ll and
test/CodeGen/WebAssembly/i64.ll after r224899.

llvm-svn: 253617

2 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index bae4f526723..dbfe00e95ed 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -228,6 +228,16 @@ WebAssemblyTargetLowering::getRegForInlineAsmConstraint(
   return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
 }
 
+bool WebAssemblyTargetLowering::isCheapToSpeculateCttz() const {
+  // Assume ctz is a relatively cheap operation.
+  return true;
+}
+
+bool WebAssemblyTargetLowering::isCheapToSpeculateCtlz() const {
+  // Assume clz is a relatively cheap operation.
+  return true;
+}
+
 //===----------------------------------------------------------------------===//
 // WebAssembly Lowering private implementation.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
index c79ffb29c25..3621571151a 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
@@ -52,6 +52,8 @@ private:
   std::pair<unsigned, const TargetRegisterClass *>
   getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
                                StringRef Constraint, MVT VT) const override;
+  bool isCheapToSpeculateCttz() const override;
+  bool isCheapToSpeculateCtlz() const override;
 
   SDValue LowerCall(CallLoweringInfo &CLI,
                     SmallVectorImpl<SDValue> &InVals) const override;