[clang] [Clang][x86]: allow PCLMULQDQ intrinsics to be used in constexpr (PR #169214)

[Simon Pilgrim via cfe-commits]

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@@ -1,17 +1,30 @@
 // RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -emit-llvm -o - | FileCheck %s --check-prefix AVX
 // RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -target-feature +avx512f -emit-llvm -o - | FileCheck %s --check-prefixes AVX,AVX512
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -emit-llvm -o - -std=c++11 | FileCheck %s --check-prefix AVX
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -target-feature +avx512f -emit-llvm -o - -std=c++11 | FileCheck %s --check-prefixes AVX,AVX512
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -emit-llvm -o - -std=c++11 -fexperimental-new-constant-interpreter | FileCheck %s --check-prefix AVX
+// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +vpclmulqdq -target-feature +avx512f -emit-llvm -o - -std=c++11 -fexperimental-new-constant-interpreter | FileCheck %s --check-prefixes AVX,AVX512
 
 #include <immintrin.h>
+#include "builtin_test_helpers.h"
 
 __m256i test_mm256_clmulepi64_epi128(__m256i A, __m256i B) {
   // AVX: @llvm.x86.pclmulqdq.256
   return _mm256_clmulepi64_epi128(A, B, 0);
 }
 
+// Test constexpr evaluation for _mm256_clmulepi64_epi128
+// Each 128-bit lane is processed independently
+TEST_CONSTEXPR(match_m256i(_mm256_clmulepi64_epi128(((__m256i){0x1ULL, 0x0ULL, 0x2ULL, 0x0ULL}), ((__m256i){0x3ULL, 0x0ULL, 0x5ULL, 0x0ULL}), 0x00), 0x3ULL, 0x0ULL, 0xaULL, 0x0ULL));
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RKSimon wrote:

You might be able to run the runtime test on godbolt, capture the stdout and compare against the local constexpr version?

https://github.com/llvm/llvm-project/pull/169214