[clang] 0638028 - [3/15][Clang][RISCV][NFC] Clarify edge cases of RVVIntrinsic::getSupportedMaskedPolicies for clarity

[via cfe-commits]

Author: eopXD
Date: 2023-01-24T00:07:33-08:00
New Revision: 063802843c20a49cf53a1fd380565ebfe29ee83f

URL: https://github.com/llvm/llvm-project/commit/063802843c20a49cf53a1fd380565ebfe29ee83f
DIFF: https://github.com/llvm/llvm-project/commit/063802843c20a49cf53a1fd380565ebfe29ee83f.diff

LOG: [3/15][Clang][RISCV][NFC] Clarify edge cases of RVVIntrinsic::getSupportedMaskedPolicies for clarity

This is the 3rd commit of a patch-set that aims to change the default policy
for RVV intrinsics from TAMU to TAMA.

Please refer to the cover letter in the 1st commit (D141573) for an
overview.

Reviewed By: kito-cheng

Differential Revision: https://reviews.llvm.org/D141575

Added: 
    

Modified: 
    clang/lib/Support/RISCVVIntrinsicUtils.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Support/RISCVVIntrinsicUtils.cpp b/clang/lib/Support/RISCVVIntrinsicUtils.cpp
index 93ade07b583b7..18b8ca54b7b6a 100644
--- a/clang/lib/Support/RISCVVIntrinsicUtils.cpp
+++ b/clang/lib/Support/RISCVVIntrinsicUtils.cpp
@@ -13,6 +13,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <numeric>
 #include <optional>
@@ -992,16 +993,18 @@ RVVIntrinsic::getSupportedMaskedPolicies(bool HasTailPolicy,
                    Policy::PolicyType::Undisturbed), // TUMU
             Policy(Policy::PolicyType::Agnostic,
                    Policy::PolicyType::Undisturbed)}; // TAMU
-
-  if (HasTailPolicy)
+  if (HasTailPolicy && !HasMaskPolicy)
     return {Policy(Policy::PolicyType::Undisturbed,
                    Policy::PolicyType::Agnostic, true), // TUM
             Policy(Policy::PolicyType::Agnostic, Policy::PolicyType::Agnostic,
                    true)}; // TAM
-
-  return {
-      Policy(Policy::PolicyType::Omit, Policy::PolicyType::Agnostic),     // MA
-      Policy(Policy::PolicyType::Omit, Policy::PolicyType::Undisturbed)}; // MU
+  if (!HasTailPolicy && HasMaskPolicy)
+    return {
+        Policy(Policy::PolicyType::Omit, Policy::PolicyType::Agnostic), // MA
+        Policy(Policy::PolicyType::Omit,
+               Policy::PolicyType::Undisturbed)}; // MU
+  llvm_unreachable("An RVV instruction should not be without both tail policy "
+                   "and mask policy");
 }
 
 void RVVIntrinsic::updateNamesAndPolicy(bool IsMasked, bool HasPolicy,