[libc-commits] [libc] [libc] Add a "Q" length modifier to support __float128 in printf (PR #199110)

[Michael Jones via libc-commits]

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@@ -1521,9 +1635,26 @@ TEST(LlvmLibcSPrintfTest, FloatDecimalConv) {
   ASSERT_STREQ_LEN(written, buff, "+0.126        0001256.000");
 }
 
+template <typename T, char M> struct TypeAndLengthModifier {
+  using Type = T;
+  constexpr static char kCharValue = M;
+};
+
+#if defined(LIBC_SPRINTF_TEST_Q_MODIFIER)
+using LongDoubleFloat128TypesAndModifiers =
+    LIBC_NAMESPACE::testing::TypeList<TypeAndLengthModifier<long double, 'L'>,
+                                      TypeAndLengthModifier<float128, 'Q'>>;
+#else
+using LongDoubleFloat128TypesAndModifiers =
+    LIBC_NAMESPACE::testing::TypeList<TypeAndLengthModifier<long double, 'L'>>;
+#endif // LIBC_SPRINTF_TEST_Q_MODIFIER
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michaelrj-google wrote:

I don't think it's necessary to replace the `L` with a `Q`. It would be simpler to have separate tests for the `Q` cases.

https://github.com/llvm/llvm-project/pull/199110