[clang] [clang] constexpr built-in reduce min/max function. (PR #120866)

[Simon Pilgrim via cfe-commits]

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@@ -838,3 +838,18 @@ static_assert(__builtin_elementwise_sub_sat((1 << 31), 42) == (1 << 31));
 static_assert(__builtin_elementwise_sub_sat(0U, 1U) == 0U);
 static_assert(__builtin_bit_cast(unsigned, __builtin_elementwise_sub_sat((vector4char){5, 4, 3, 2}, (vector4char){1, 1, 1, 1})) == (LITTLE_END ? 0x01020304 : 0x04030201));
 static_assert(__builtin_bit_cast(unsigned long long, __builtin_elementwise_sub_sat((vector4short){(short)0x8000, (short)0x8001, (short)0x8002, (short)0x8003}, (vector4short){7, 8, 9, 10}) == (LITTLE_END ? 0x8000800080008000 : 0x8000800080008000)));
+
+static_assert(__builtin_reduce_min((vector4char){}) == 0);
+static_assert(__builtin_reduce_min((vector4char){(char)0x11, (char)0x22, (char)0x44, (char)0x88}) == (char)0x88);
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RKSimon wrote:

(pedantic) Move this to be with the other __builtin_reduce_* intrinsics

https://github.com/llvm/llvm-project/pull/120866