Merge #637

637: Add support for const bool and const float r=philberty a=dkm

From Mark Wielaard : https://gcc.gnu.org/pipermail/gcc-rust/2021-August/000143.html

> Handle BOOL and FLOAT in ConstFoldExpr::visit (HIR::LiteralExpr) to
> make it possible to create const bool, f32 and f64 constants. Add a
> new testcase "primconsts.rs". Not yet handled are const char and &str
> types.

Co-authored-by: Mark Wielaard <mark@klomp.org>

2 files changed, 102 insertions, 0 deletions

diff --git a/gcc/rust/typecheck/rust-hir-const-fold.h b/gcc/rust/typecheck/rust-hir-const-fold.h
index f6c6616..8efbb18 100644
--- a/gcc/rust/typecheck/rust-hir-const-fold.h
+++ b/gcc/rust/typecheck/rust-hir-const-fold.h
@@ -315,6 +315,36 @@ public:
 	}
 	return;
 
+	case HIR::Literal::BOOL: {
+	  bool bval = literal_value->as_string ().compare ("true") == 0;
+	  folded = ctx->get_backend ()->boolean_constant_expression (bval);
+	}
+	return;
+
+	case HIR::Literal::FLOAT: {
+	  mpfr_t fval;
+	  if (mpfr_init_set_str (fval, literal_value->as_string ().c_str (), 10,
+				 MPFR_RNDN)
+	      != 0)
+	    {
+	      rust_fatal_error (expr.get_locus (),
+				"bad floating-point number in literal");
+	      return;
+	    }
+
+	  TyTy::BaseType *tyty = nullptr;
+	  if (!tyctx->lookup_type (expr.get_mappings ().get_hirid (), &tyty))
+	    {
+	      rust_fatal_error (expr.get_locus (),
+				"did not resolve type for this literal expr");
+	      return;
+	    }
+
+	  Btype *type = ConstFoldType::fold (tyty, ctx->get_backend ());
+	  folded = ctx->get_backend ()->float_constant_expression (type, fval);
+	}
+	return;
+
 	/* handle other literals */
 
       default:
diff --git a/gcc/testsuite/rust/compile/torture/primconsts.rs b/gcc/testsuite/rust/compile/torture/primconsts.rs
new file mode 100644
index 0000000..bcf9456
--- /dev/null
+++ b/gcc/testsuite/rust/compile/torture/primconsts.rs
@@ -0,0 +1,72 @@
+const TRUE: bool = true;
+const FALSE: bool = !TRUE;
+
+const U8ZERO: u8 = 0;
+const U8ONE: u8 = U8ZERO + 1;
+const U16ZERO: u16 = 0;
+const U16ONE: u16 = U16ZERO + 1;
+const U32ZERO: u32 = 0;
+const U32ONE: u32 = U32ZERO + 1;
+const U64ZERO: u64 = 0;
+const U64ONE: u64 = U64ZERO + 1;
+const U128ZERO: u128 = 0;
+const U128ONE: u128 = U128ZERO + 1;
+
+const I8ZERO: i8 = 0;
+const I8ONE: i8 = I8ZERO + 1;
+const I16ZERO: i16 = 0;
+const I16ONE: i16 = I16ZERO + 1;
+const I32ZERO: i32 = 0;
+const I32ONE: i32 = I32ZERO + 1;
+const I64ZERO: i64 = 0;
+const I64ONE: i64 = I64ZERO + 1;
+const I128ZERO: i128 = 0;
+const I128ONE: i128 = I128ZERO + 1;
+
+const F32ZERO: f32 = 0.0;
+const F32ONE: f32 = F32ZERO + 1.0;
+const F64ZERO: f64 = 0.0;
+const F64ONE: f64 = F64ZERO + 1.0;
+
+const USIZEZERO: usize = 0;
+const USIZEONE: usize = USIZEZERO + 1;
+const ISIZEZERO: isize = 0;
+const ISIZEONE: isize = ISIZEZERO + 1;
+
+/* Not yet supported 
+const CHARPI: char = '\u{03C0}';
+const STRHELLO: &str = "Hello World!";
+*/
+
+extern "C" { fn abort (); }
+
+pub fn main ()
+{
+  if TRUE == FALSE { unsafe { abort (); } }
+  if U8ZERO > U8ONE { unsafe { abort (); } }
+  if U16ZERO > U16ONE { unsafe { abort (); } }
+  if U32ZERO > U32ONE { unsafe { abort (); } }
+  if U64ZERO > U64ONE { unsafe { abort (); } }
+  if U128ZERO > U128ONE { unsafe { abort (); } }
+
+  if I8ONE <= I8ZERO { unsafe { abort (); } }
+  if I16ONE <= I16ZERO { unsafe { abort (); } }
+  if I32ONE <= I32ZERO { unsafe { abort (); } }
+  if I64ONE <= I64ZERO { unsafe { abort (); } }
+  if I128ONE <= I128ZERO { unsafe { abort (); } }
+
+  if F32ZERO + F32ONE != F32ONE { unsafe { abort (); } }
+  if F64ZERO + F64ONE != F64ONE { unsafe { abort (); } }
+
+  if USIZEZERO + USIZEONE - USIZEONE + USIZEZERO != USIZEZERO
+    {
+      unsafe { abort (); }
+    }
+  if ISIZEZERO + ISIZEONE - ISIZEONE + ISIZEZERO != ISIZEZERO
+    {
+      unsafe { abort (); }
+    }
+
+ // if CHARPI != '\u{03c0}'  { unsafe { abort (); } }
+ // if STRHELLO != "Hello World!" { unsafe { abort (); } }
+}