[X86] Emit Warnings for frontend options to enable knl/knm specific ISAs. (#75580)

Since Knight Landing and Knight Mill microarchitectures are EOL, we
would like to remove intrinsic supports for its specific ISA in LLVM 19.
In LLVM 18, we will first emit a warning for the usage.

7 files changed, 32 insertions, 6 deletions

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 980be4fe0ef7..1b2d7c86a962 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -936,6 +936,14 @@ X86 Support
 - Support ISA of ``AVX10.1``.
 - ``-march=pantherlake`` and ``-march=clearwaterforest`` are now supported.
 - Added ABI handling for ``__float128`` to match with GCC.
+- Emit warnings for options to enable knl/knm specific ISAs: AVX512PF, AVX512ER
+  and PREFETCHWT1. From next version (LLVM 19), these ISAs' intrinsic supports
+  will be deprecated:
+  * intrinsic series of *_exp2a23_*
+  * intrinsic series of *_rsqrt28_*
+  * intrinsic series of *_rcp28_*
+  * intrinsic series of *_prefetch_i[3|6][2|4]gather_*
+  * intrinsic series of *_prefetch_i[3|6][2|4]scatter_*
 
 Arm and AArch64 Support
 ^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td b/clang/include/clang/Basic/DiagnosticCommonKinds.td
index 65a33f61a694..72952b08c04a 100644
--- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
+++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
@@ -349,6 +349,9 @@ def warn_invalid_feature_combination : Warning<
 def warn_target_unrecognized_env : Warning<
   "mismatch between architecture and environment in target triple '%0'; did you mean '%1'?">,
   InGroup<InvalidCommandLineArgument>;
+def warn_knl_knm_isa_support_removed : Warning<
+  "KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.">,
+  InGroup<DiagGroup<"knl-knm-isa-support-removed">>;
 
 // Source manager
 def err_cannot_open_file : Error<"cannot open file '%0': %1">, DefaultFatal;
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 3deaa19f8d4f..64e281b888a9 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -295,11 +295,13 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasAVX512BF16 = true;
     } else if (Feature == "+avx512er") {
       HasAVX512ER = true;
+      Diags.Report(diag::warn_knl_knm_isa_support_removed);
     } else if (Feature == "+avx512fp16") {
       HasAVX512FP16 = true;
       HasLegalHalfType = true;
     } else if (Feature == "+avx512pf") {
       HasAVX512PF = true;
+      Diags.Report(diag::warn_knl_knm_isa_support_removed);
     } else if (Feature == "+avx512dq") {
       HasAVX512DQ = true;
     } else if (Feature == "+avx512bitalg") {
@@ -358,6 +360,7 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
       HasPREFETCHI = true;
     } else if (Feature == "+prefetchwt1") {
       HasPREFETCHWT1 = true;
+      Diags.Report(diag::warn_knl_knm_isa_support_removed);
     } else if (Feature == "+clzero") {
       HasCLZERO = true;
     } else if (Feature == "+cldemote") {
diff --git a/clang/test/CodeGen/X86/avx512er-builtins.c b/clang/test/CodeGen/X86/avx512er-builtins.c
index ee31236a3c01..11ec6aabec1e 100644
--- a/clang/test/CodeGen/X86/avx512er-builtins.c
+++ b/clang/test/CodeGen/X86/avx512er-builtins.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +avx512f -target-feature +avx512er -emit-llvm -o - -Wall -Werror | FileCheck %s
+// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +avx512f -target-feature +avx512er -emit-llvm -o - -Wall | FileCheck %s
 
 
 #include <immintrin.h>
diff --git a/clang/test/CodeGen/X86/avx512pf-builtins.c b/clang/test/CodeGen/X86/avx512pf-builtins.c
index 4ca70f578796..3a117ed6a946 100644
--- a/clang/test/CodeGen/X86/avx512pf-builtins.c
+++ b/clang/test/CodeGen/X86/avx512pf-builtins.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +avx512pf -emit-llvm -o - -Wall -Werror | FileCheck %s
+// RUN: %clang_cc1 -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-apple-darwin -target-feature +avx512pf -emit-llvm -o - -Wall | FileCheck %s
 
 
 #include <immintrin.h>
diff --git a/clang/test/Driver/cl-x86-flags.c b/clang/test/Driver/cl-x86-flags.c
index 51b16f0ce354..716b02f02a15 100644
--- a/clang/test/Driver/cl-x86-flags.c
+++ b/clang/test/Driver/cl-x86-flags.c
@@ -69,7 +69,10 @@
 // RUN: %clang_cl -m32 -arch:avx2 --target=i386-pc-windows -### -- 2>&1 %s | FileCheck -check-prefix=avx2 %s
 // avx2: invalid /arch: argument
 
-// RUN: %clang_cl -m32 -arch:AVX512F --target=i386-pc-windows /c /Fo%t.obj -Xclang -verify -DTEST_32_ARCH_AVX512F -- %s
+// RUN: %clang_cl -m32 -arch:AVX512F --target=i386-pc-windows /c /Fo%t.obj -Xclang -verify=KNL1 -DTEST_32_ARCH_AVX512F -- %s
+// KNL1-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// KNL1-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// KNL1-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
 #if defined(TEST_32_ARCH_AVX512F)
 #if _M_IX86_FP != 2 || !__AVX__ || !__AVX2__ || !__AVX512F__  || __AVX512BW__
 #error fail
@@ -109,7 +112,10 @@
 // RUN: %clang_cl -m64 -arch:avx2 --target=x86_64-pc-windows -### -- 2>&1 %s | FileCheck -check-prefix=avx264 %s
 // avx264: invalid /arch: argument
 
-// RUN: %clang_cl -m64 -arch:AVX512F --target=i386-pc-windows /c /Fo%t.obj -Xclang -verify -DTEST_64_ARCH_AVX512F -- %s
+// RUN: %clang_cl -m64 -arch:AVX512F --target=i386-pc-windows /c /Fo%t.obj -Xclang -verify=KNL2 -DTEST_64_ARCH_AVX512F -- %s
+// KNL2-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// KNL2-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// KNL2-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
 #if defined(TEST_64_ARCH_AVX512F)
 #if _M_IX86_FP || !__AVX__ || !__AVX2__ || !__AVX512F__  || __AVX512BW__
 #error fail
diff --git a/clang/test/Frontend/x86-target-cpu.c b/clang/test/Frontend/x86-target-cpu.c
index 6c8502ac2c21..6b99b2c8574a 100644
--- a/clang/test/Frontend/x86-target-cpu.c
+++ b/clang/test/Frontend/x86-target-cpu.c
@@ -15,8 +15,14 @@
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu cannonlake -verify %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu icelake-client -verify %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu icelake-server -verify %s
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu knl -verify %s
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu knm -verify %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu knl -verify=knl %s
+// knl-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// knl-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// knl-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu knm -verify=knm %s
+// knm-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// knm-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
+// knm-warning@*:* {{KNL, KNM related Intel Xeon Phi CPU's specific ISA's supports will be removed in LLVM 19.}}
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu bonnell -verify %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu silvermont -verify %s
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -target-cpu k8 -verify %s