[PATCH] D137399: [clang][Interp] Emit negated integers directly as constants

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D137399

Files:
  clang/lib/AST/Interp/ByteCodeExprGen.cpp


Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1518,6 +1518,13 @@
     // The Inv doesn't change anything, so skip it if we don't need the result.
     return DiscardResult ? this->emitPop(*T, E) : this->emitInvBool(E);
   case UO_Minus: // -x
+    // Emit negated integers directly.
+    if (const auto *IL = dyn_cast<IntegerLiteral>(SubExpr)) {
+      if (DiscardResult)
+        return true;
+      APSInt V = APSInt(IL->getValue(), /*IsUnsigned=*/false);
+      return this->emitConst(-V, E);
+    }
     if (!this->visit(SubExpr))
       return false;
     return DiscardResult ? this->emitPop(*T, E) : this->emitNeg(*T, E);



Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1518,6 +1518,13 @@
     // The Inv doesn't change anything, so skip it if we don't need the result.
     return DiscardResult ? this->emitPop(*T, E) : this->emitInvBool(E);
   case UO_Minus: // -x
+    // Emit negated integers directly.
+    if (const auto *IL = dyn_cast<IntegerLiteral>(SubExpr)) {
+      if (DiscardResult)
+        return true;
+      APSInt V = APSInt(IL->getValue(), /*IsUnsigned=*/false);
+      return this->emitConst(-V, E);
+    }
     if (!this->visit(SubExpr))
       return false;
     return DiscardResult ? this->emitPop(*T, E) : this->emitNeg(*T, E);

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