[EVM][ConstantRange] Add support for signextend intrinsic

Signed-off-by: Vladimir Radosavljevic <[email protected]>

Author: vladimirradosavljevic

llvm/include/llvm/IR/ConstantRange.h

@@ -554,6 +554,8 @@ class [[nodiscard]] ConstantRange {
   /// Calculate ctpop range.
   ConstantRange ctpop() const;
 
+  ConstantRange evmSignExtend(const ConstantRange &Other) const;
+
   /// Represents whether an operation on the given constant range is known to
   /// always or never overflow.
   enum class OverflowResult {

llvm/include/llvm/IR/IntrinsicsEVM.td

@@ -91,8 +91,8 @@ def int_evm_sha3
                  NoCapture<ArgIndex<0>>, IntrWillReturn]>;
 
 def int_evm_signextend
-    : Intrinsic<[llvm_i256_ty], [llvm_i256_ty, llvm_i256_ty],
-                [IntrNoMem, IntrWillReturn]>;
+    : DefaultAttrsIntrinsic<[llvm_i256_ty], [llvm_i256_ty, llvm_i256_ty],
+                            [IntrNoMem, IntrSpeculatable]>;
 
 def int_evm_byte : Intrinsic<[llvm_i256_ty], [llvm_i256_ty, llvm_i256_ty],
                              [IntrNoMem, IntrWillReturn]>;

llvm/lib/IR/ConstantRange.cpp

@@ -27,6 +27,7 @@
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsEVM.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/Support/Compiler.h"
@@ -1009,6 +1010,7 @@ bool ConstantRange::isIntrinsicSupported(Intrinsic::ID IntrinsicID) {
   case Intrinsic::ctlz:
   case Intrinsic::cttz:
   case Intrinsic::ctpop:
+  case Intrinsic::evm_signextend:
     return true;
   default:
     return false;
@@ -1018,6 +1020,8 @@ bool ConstantRange::isIntrinsicSupported(Intrinsic::ID IntrinsicID) {
 ConstantRange ConstantRange::intrinsic(Intrinsic::ID IntrinsicID,
                                        ArrayRef<ConstantRange> Ops) {
   switch (IntrinsicID) {
+  case Intrinsic::evm_signextend:
+    return Ops[0].evmSignExtend(Ops[1]);
   case Intrinsic::uadd_sat:
     return Ops[0].uadd_sat(Ops[1]);
   case Intrinsic::usub_sat:
@@ -1953,6 +1957,26 @@ ConstantRange ConstantRange::ctpop() const {
   return CR1.unionWith(CR2);
 }
 
+ConstantRange ConstantRange::evmSignExtend(const ConstantRange &Other) const {
+  unsigned BitWidth = getBitWidth();
+  if (BitWidth != 256)
+    return getFull();
+
+  if (isEmptySet() || Other.isEmptySet())
+    return getEmpty();
+
+  if (!isSingleElement())
+    return getFull();
+
+  // ByteIdx must be in range [0, 31].
+  uint64_t ByteIdx = getSingleElement()->getZExtValue();
+  if (ByteIdx >= BitWidth / 8)
+    return getFull();
+
+  unsigned Width = (ByteIdx + 1) * 8;
+  return Other.truncate(Width).signExtend(BitWidth);
+}
+
 ConstantRange::OverflowResult ConstantRange::unsignedAddMayOverflow(
     const ConstantRange &Other) const {
   if (isEmptySet() || Other.isEmptySet())