[clang] [C99] Claim conformance for _Complex support (PR #88161)
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Tue Apr 9 10:34:17 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Aaron Ballman (AaronBallman)
<details>
<summary>Changes</summary>
There's so much overlap between the cited papers so this condenses the status page into a single entry rather than trying to test conformance against multiple papers doing conflicting things.
---
Full diff: https://github.com/llvm/llvm-project/pull/88161.diff
2 Files Affected:
- (added) clang/test/C/C99/n809.c (+97)
- (modified) clang/www/c_status.html (+8-22)
``````````diff
diff --git a/clang/test/C/C99/n809.c b/clang/test/C/C99/n809.c
new file mode 100644
index 00000000000000..8d26744443eec4
--- /dev/null
+++ b/clang/test/C/C99/n809.c
@@ -0,0 +1,97 @@
+// RUN: %clang_cc1 -verify -std=c99 %s
+
+/* WG14 N620, N638, N657, N694, N809: Yes*
+ * Complex and imaginary support in <complex.h>
+ *
+ * NB: Clang supports _Complex but not _Imaginary. In C99, _Complex support is
+ * required outside of freestanding, but _Imaginary support is fully optional.
+ * In C11, both are made fully optional. We claim full conformance because we
+ * are actually conforming, but this gets an asterisk because it's also only
+ * partially implemented in a way and users should know about that.
+ *
+ * Because the functionality is so intertwined between the various papers,
+ * we're testing all of the functionality in one file.
+ */
+
+// Demonstrate that we support spelling complex floating-point objects.
+float _Complex f1;
+_Complex float f2;
+
+double _Complex d1;
+_Complex double d2;
+
+long double _Complex ld1;
+_Complex long double ld2;
+
+// Show that we don't support spelling imaginary types.
+float _Imaginary fi1; // expected-error {{imaginary types are not supported}}
+_Imaginary float fi2; // expected-error {{imaginary types are not supported}}
+
+double _Imaginary di1; // expected-error {{imaginary types are not supported}}
+_Imaginary double di2; // expected-error {{imaginary types are not supported}}
+
+long double _Imaginary ldi1; // expected-error {{imaginary types are not supported}}
+_Imaginary long double ldi2; // expected-error {{imaginary types are not supported}}
+
+// Each complex type has the same representation and alignment as an array
+// containing two elements of the corresponding real type.
+_Static_assert(sizeof(float _Complex) == sizeof(struct { float mem[2]; }), "");
+_Static_assert(_Alignof(float _Complex) == _Alignof(struct { float mem[2]; }), "");
+
+_Static_assert(sizeof(double _Complex) == sizeof(struct { double mem[2]; }), "");
+_Static_assert(_Alignof(double _Complex) == _Alignof(struct { double mem[2]; }), "");
+
+_Static_assert(sizeof(long double _Complex) == sizeof(struct { long double mem[2]; }), "");
+_Static_assert(_Alignof(long double _Complex) == _Alignof(struct { long double mem[2]; }), "");
+
+// The first element corresponds to the real part and the second element
+// corresponds to the imaginary part.
+_Static_assert(__real((float _Complex){ 1.0f, 2.0f }) == 1.0f, "");
+_Static_assert(__imag((float _Complex){ 1.0f, 2.0f }) == 2.0f, "");
+
+_Static_assert(__real((double _Complex){ 1.0, 2.0 }) == 1.0, "");
+_Static_assert(__imag((double _Complex){ 1.0, 2.0 }) == 2.0, "");
+
+_Static_assert(__real((long double _Complex){ 1.0L, 2.0L }) == 1.0L, "");
+_Static_assert(__imag((long double _Complex){ 1.0L, 2.0L }) == 2.0L, "");
+
+// When a real value is converted to a complex value, the real part follows the
+// usual conversion rules and the imaginary part should be zero.
+_Static_assert(__real((float _Complex)1.0f) == 1.0f, "");
+_Static_assert(__imag((float _Complex)1.0f) == 0.0f, "");
+
+_Static_assert(__real((double _Complex)1.0f) == 1.0, "");
+_Static_assert(__imag((double _Complex)1.0f) == 0.0, "");
+
+_Static_assert(__real((long double _Complex)1.0f) == 1.0L, "");
+_Static_assert(__imag((long double _Complex)1.0f) == 0.0L, "");
+
+// When a complex value is converted to a real value, the real part follows the
+// usual conversion rules and the imaginary part is discarded.
+_Static_assert((float)(float _Complex){ 1.0f, 2.0f } == 1.0f, "");
+_Static_assert((double)(float _Complex){ 1.0f, 2.0f } == 1.0, "");
+_Static_assert((long double)(float _Complex){ 1.0f, 2.0f } == 1.0L, "");
+
+// Complex values are only equal if both the real and imaginary parts are equal.
+_Static_assert((float _Complex){ 1.0f, 2.0f } == (float _Complex){ 1.0f, 2.0f }, "");
+_Static_assert((double _Complex){ 1.0, 2.0 } == (double _Complex){ 1.0, 2.0 }, "");
+_Static_assert((long double _Complex){ 1.0L, 2.0L } == (long double _Complex){ 1.0L, 2.0L }, "");
+
+_Static_assert((float _Complex){ 1.0f, 2.0f } != (float _Complex){ 2.0f, 0.0f }, "");
+_Static_assert((double _Complex){ 1.0, 2.0 } != (double _Complex){ 2.0, 0.0 }, "");
+_Static_assert((long double _Complex){ 1.0L, 2.0L } != (long double _Complex){ 2.0L, 0.0L }, "");
+
+// You cannot use relational operator on complex values.
+int i1 = (float _Complex){ 1.0f, 2.0f } < 10; // expected-error {{invalid operands to binary expression}}
+int i2 = (double _Complex){ 1.0f, 2.0f } > 10; // expected-error {{invalid operands to binary expression}}
+int i3 = (long double _Complex){ 1.0f, 2.0f } <= 10; // expected-error {{invalid operands to binary expression}}
+int i4 = (float _Complex){ 1.0f, 2.0f } >= 10; // expected-error {{invalid operands to binary expression}}
+
+// As a type specifier, _Complex cannot appear alone; however, we support it as
+// an extension by assuming _Complex double.
+_Complex c = 1.0f; // expected-warning {{plain '_Complex' requires a type specifier; assuming '_Complex double'}}
+// Because we don't support imaginary types, we don't extend the extension to
+// that type specifier.
+// FIXME: the warning diagnostic here is incorrect and should not be emitted.
+_Imaginary i = 1.0f; // expected-warning {{plain '_Complex' requires a type specifier; assuming '_Complex double'}} \
+ expected-error {{imaginary types are not supported}}
diff --git a/clang/www/c_status.html b/clang/www/c_status.html
index 7ee1d2b507e88c..99a65bfb0a48e5 100644
--- a/clang/www/c_status.html
+++ b/clang/www/c_status.html
@@ -132,29 +132,11 @@ <h2 id="c99">C99 implementation status</h2>
<td>Unknown</td>
<td class="full" align="center">Yes</td>
</tr>
- <tr id="complex">
- <td rowspan="6">complex and imaginary support in <complex.h></td>
+ <tr>
+ <td>complex and imaginary support in <complex.h></td>
+ <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n693.ps">N693</a></td>
+ <td class="full" align="center">Yes <a href="#complex">(1)</a></td>
</tr>
- <tr>
- <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n620.ps">N620</a></td>
- <td class="unknown" align="center">Unknown</td>
- </tr>
- <tr>
- <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n638.ps">N638</a></td>
- <td class="unknown" align="center">Unknown</td>
- </tr>
- <tr>
- <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n657.ps">N657</a></td>
- <td class="unknown" align="center">Unknown</td>
- </tr>
- <tr>
- <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n694.ps">N694</a></td>
- <td class="unknown" align="center">Unknown</td>
- </tr>
- <tr>
- <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n809.ps">N809</a></td>
- <td class="unknown" align="center">Unknown</td>
- </tr>
<tr>
<td>type-generic math macros in <tgmath.h></td>
<td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n693.ps">N693</a></td>
@@ -373,6 +355,10 @@ <h2 id="c99">C99 implementation status</h2>
<td class="full" align="center">Yes</td>
</tr>
</table>
+<span id="complex">(1): Clang supports <code>_Complex</code> type specifiers but
+does not support <code>_Imaginary</code> type specifiers. Support for
+<code>_Imaginary</code> is optional in C99 which is why Clang is fully conforming.
+</span>
</details>
<h2 id="c11">C11 implementation status</h2>
``````````
</details>
https://github.com/llvm/llvm-project/pull/88161
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