[gcc r15-8378] gccrs: [gccrs#3141] Remove double negation by returning CompileExpr::Compile early

[Arthur Cohen]

https://gcc.gnu.org/g:8ca55013c295ab4964e21f34083c24ea147768dd

commit r15-8378-g8ca55013c295ab4964e21f34083c24ea147768dd
Author: JoanVC <github-91yu@joanvc.cat>
Date:   Sun Sep 15 15:59:34 2024 +0200

    gccrs: [gccrs#3141] Remove double negation by returning CompileExpr::Compile early
    
    Fixes gccrs#3141.
    
    gcc/rust/ChangeLog:
    
            * backend/rust-compile-expr.cc
    
    Signed-off-by: Joan Vilardaga <github-91yu@joanvc.cat>

Diff:
---
 gcc/rust/backend/rust-compile-expr.cc | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/gcc/rust/backend/rust-compile-expr.cc b/gcc/rust/backend/rust-compile-expr.cc
index 0c0d993acded..6458c42d78d1 100644
--- a/gcc/rust/backend/rust-compile-expr.cc
+++ b/gcc/rust/backend/rust-compile-expr.cc
@@ -237,6 +237,8 @@ CompileExpr::visit (HIR::NegationExpr &expr)
   auto op = expr.get_expr_type ();
 
   const auto literal_expr = expr.get_expr ().get ();
+
+  // If it's a negated integer/float literal, we can return early
   if (op == NegationOperator::NEGATE
       && literal_expr->get_expression_type () == HIR::Expr::ExprType::Lit)
     {
@@ -246,10 +248,12 @@ CompileExpr::visit (HIR::NegationExpr &expr)
 	  || lit_type == HIR::Literal::LitType::FLOAT)
 	{
 	  new_literal_expr->set_negative ();
+	  translated = CompileExpr::Compile (literal_expr, ctx);
+	  return;
 	}
     }
-  auto negated_expr = CompileExpr::Compile (literal_expr, ctx);
 
+  auto negated_expr = CompileExpr::Compile (literal_expr, ctx);
   auto location = expr.get_locus ();
 
   // this might be an operator overload situation lets check
@@ -1531,11 +1535,6 @@ CompileExpr::compile_integer_literal (const HIR::LiteralExpr &expr,
 		     tyty->get_name ().c_str ());
       return error_mark_node;
     }
-  // Other tests break if we don't reverse the negation
-  if (expr.is_negative ())
-    {
-      mpz_neg (ival, ival);
-    }
 
   tree result = wide_int_to_tree (type, wi::from_mpz (type, ival, true));