[clang] c2a892f - Revert "[clang][bytecode] Implement bitcasts to floating-point values (#114485)"

[Timm Bäder via cfe-commits]

Author: Timm Bäder
Date: 2024-11-02T01:54:38+01:00
New Revision: c2a892f49ae0603949db88aacab7bbc11117aa52

URL: https://github.com/llvm/llvm-project/commit/c2a892f49ae0603949db88aacab7bbc11117aa52
DIFF: https://github.com/llvm/llvm-project/commit/c2a892f49ae0603949db88aacab7bbc11117aa52.diff

LOG: Revert "[clang][bytecode] Implement bitcasts to floating-point values (#114485)"

This reverts commit c752efbdcc1ebd81f879633d6b798248064e2ae2.

This broke bots:
 - https://lab.llvm.org/buildbot/#/builders/13/builds/3268
 - https://lab.llvm.org/buildbot/#/builders/42/builds/1718

Added: 
    

Modified: 
    clang/lib/AST/ByteCode/Interp.h
    clang/test/AST/ByteCode/builtin-bit-cast.cpp

Removed: 
    clang/test/AST/ByteCode/builtin-bit-cast-long-double.cpp


################################################################################
diff  --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index 52d3a19ca99593..ade6f7424b1fd6 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -3062,8 +3062,7 @@ inline bool BitCast(InterpState &S, CodePtr OpPC, bool TargetIsUCharOrByte,
     return false;
 
   if constexpr (std::is_same_v<T, Floating>) {
-    assert(Sem);
-    S.Stk.push<Floating>(T::bitcastFromMemory(Buff.data(), *Sem));
+    assert(false && "Implement bitcasting to a floating type");
   } else {
     assert(!Sem);
     S.Stk.push<T>(T::bitcastFromMemory(Buff.data(), ResultBitWidth));

diff  --git a/clang/test/AST/ByteCode/builtin-bit-cast-long-double.cpp b/clang/test/AST/ByteCode/builtin-bit-cast-long-double.cpp
deleted file mode 100644
index 230680ff3ced7d..00000000000000
--- a/clang/test/AST/ByteCode/builtin-bit-cast-long-double.cpp
+++ /dev/null
@@ -1,87 +0,0 @@
-// RUN: %clang_cc1 -verify=ref,both -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s
-// RUN: %clang_cc1 -verify=ref,both -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s -fno-signed-char
-// RUN: %clang_cc1 -verify=ref,both -std=c++2a -fsyntax-only -triple aarch64_be-linux-gnu %s
-
-// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s -fexperimental-new-constant-interpreter
-// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s -fno-signed-char -fexperimental-new-constant-interpreter
-// RUN: %clang_cc1 -verify=expected,both -std=c++2a -fsyntax-only -triple aarch64_be-linux-gnu %s -fexperimental-new-constant-interpreter
-
-// both-no-diagnostics
-
-typedef decltype(nullptr) nullptr_t;
-typedef __INTPTR_TYPE__ intptr_t;
-
-static_assert(sizeof(int) == 4);
-static_assert(sizeof(long long) == 8);
-
-template <class To, class From>
-constexpr To bit_cast(const From &from) {
-  static_assert(sizeof(To) == sizeof(From));
-  return __builtin_bit_cast(To, from);
-}
-
-template <class Intermediate, class Init>
-constexpr bool check_round_trip(const Init &init) {
-  return bit_cast<Init>(bit_cast<Intermediate>(init)) == init;
-}
-
-template <class Intermediate, class Init>
-constexpr Init round_trip(const Init &init) {
-  return bit_cast<Init>(bit_cast<Intermediate>(init));
-}
-
-
-
-
-namespace test_long_double {
-#if __x86_64
-#if 0
-constexpr __int128_t test_cast_to_int128 = bit_cast<__int128_t>((long double)0); // expected-error{{must be initialized by a constant expression}}\
-                                                                                 // expected-note{{in call}}
-#endif
-constexpr long double ld = 3.1425926539;
-
-struct bytes {
-  unsigned char d[16];
-};
-
-// static_assert(round_trip<bytes>(ld), "");
-
-static_assert(round_trip<long double>(10.0L));
-
-#if 0
-constexpr bool f(bool read_uninit) {
-  bytes b = bit_cast<bytes>(ld);
-  unsigned char ld_bytes[10] = {
-    0x0,  0x48, 0x9f, 0x49, 0xf0,
-    0x3c, 0x20, 0xc9, 0x0,  0x40,
-  };
-
-  for (int i = 0; i != 10; ++i)
-    if (ld_bytes[i] != b.d[i])
-      return false;
-
-  if (read_uninit && b.d[10]) // expected-note{{read of uninitialized object is not allowed in a constant expression}}
-    return false;
-
-  return true;
-}
-
-static_assert(f(/*read_uninit=*/false), "");
-static_assert(f(/*read_uninit=*/true), ""); // expected-error{{static assertion expression is not an integral constant expression}} \
-                                            // expected-note{{in call to 'f(true)'}}
-#endif
-constexpr bytes ld539 = {
-  0x0, 0x0,  0x0,  0x0,
-  0x0, 0x0,  0xc0, 0x86,
-  0x8, 0x40, 0x0,  0x0,
-  0x0, 0x0,  0x0,  0x0,
-};
-
-constexpr long double fivehundredandthirtynine = 539.0;
-
-static_assert(bit_cast<long double>(ld539) == fivehundredandthirtynine, "");
-#else
-static_assert(round_trip<__int128_t>(34.0L));
-#endif
-}

diff  --git a/clang/test/AST/ByteCode/builtin-bit-cast.cpp b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
index a48d9549959e90..0e86da9133b33d 100644
--- a/clang/test/AST/ByteCode/builtin-bit-cast.cpp
+++ b/clang/test/AST/ByteCode/builtin-bit-cast.cpp
@@ -76,8 +76,6 @@ static_assert(check_round_trip<__int128_t>((__int128_t)34));
 static_assert(check_round_trip<__int128_t>((__int128_t)-34));
 #endif
 
-static_assert(check_round_trip<double>(17.0));
-
 
 namespace simple {
   constexpr int A = __builtin_bit_cast(int, 10);
@@ -110,7 +108,7 @@ namespace simple {
   static_assert(check_round_trip<unsigned>((int)0x12345678));
   static_assert(check_round_trip<unsigned>((int)0x87654321));
   static_assert(check_round_trip<unsigned>((int)0x0C05FEFE));
-  static_assert(round_trip<float>((int)0x0C05FEFE));
+  // static_assert(round_trip<float>((int)0x0C05FEFE));
 
 
   /// This works in GCC and in the bytecode interpreter, but the current interpreter