[llvm] [AArch64] Fix predicates for SME2p2. (PR #145315)

[Sander de Smalen via llvm-commits]

https://github.com/sdesmalen-arm created https://github.com/llvm/llvm-project/pull/145315

The following two expressions are not equal:

  (hasSVE2p2() || hasSME2p2()) && isSVEorStreamingSVEAvailable()
  (hasSVE2p2() || (hasSME2p2() && isStreaming())

If the target has +sve,+sme2p2 and the function is not a streaming function, then the former expression would evaluate to true, thus incorrectly assuming the target has SVE2p2.

This patch also removes redundant `hasSVE() from
`isSVEAvailable() && hasSVE()`, which is an NFC change.

>From 502d1b7a2726518542be7e9311d6ba85c79828e4 Mon Sep 17 00:00:00 2001
From: Sander de Smalen <sander.desmalen at arm.com>
Date: Mon, 23 Jun 2025 11:38:41 +0000
Subject: [PATCH] [AArch64] Fix predicate for SME2p2.

The following two expressions are not equal:

  (hasSVE2p2() || hasSME2p2()) && isSVEorStreamingSVEAvailable()
  (hasSVE2p2() || (hasSME2p2() && isStreaming())

If the target has +sve,+sme2p2 and the function is not a streaming
function, then the former expression would evaluate to true,
thus incorrectly assuming the target has SVE2p2.

This patch also removes redundant `hasSVE() from
`isSVEAvailable() && hasSVE()`, which is an NFC change.
---
 llvm/lib/Target/AArch64/AArch64InstrInfo.td    | 13 +++++++------
 llvm/test/CodeGen/AArch64/sve2p2-intrinsics.ll |  1 +
 llvm/test/CodeGen/AArch64/zeroing-forms-ext.ll |  7 +++++--
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 0f3f24f0853c9..b1f2cdec9f033 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -249,13 +249,13 @@ def HasSVE_or_SME
                 AssemblerPredicateWithAll<(any_of FeatureSVE, FeatureSME),
                 "sve or sme">;
 def HasNonStreamingSVE_or_SME2p2
-    : Predicate<"(Subtarget->isSVEAvailable() && Subtarget->hasSVE()) ||"
-                "(Subtarget->isSVEorStreamingSVEAvailable() && Subtarget->hasSME2p2())">,
+    : Predicate<"Subtarget->isSVEAvailable() ||"
+                "(Subtarget->isStreaming() && Subtarget->hasSME2p2())">,
                 AssemblerPredicateWithAll<(any_of FeatureSVE, FeatureSME2p2),
                 "sve or sme2p2">;
 def HasNonStreamingSVE_or_SSVE_FEXPA
-    : Predicate<"(Subtarget->isSVEAvailable() && Subtarget->hasSVE()) ||"
-                "(Subtarget->isSVEorStreamingSVEAvailable() && Subtarget->hasSSVE_FEXPA())">,
+    : Predicate<"Subtarget->isSVEAvailable() ||"
+                "(Subtarget->isStreaming() && Subtarget->hasSSVE_FEXPA())">,
                 AssemblerPredicateWithAll<(any_of FeatureSVE, FeatureSSVE_FEXPA),
                 "sve or ssve-fexpa">;
 
@@ -287,12 +287,13 @@ def HasSVE2p1_or_SME2p1
                 "sme2p1 or sve2p1">;
 
 def HasSVE2p2_or_SME2p2
-    : Predicate<"Subtarget->isSVEorStreamingSVEAvailable() && (Subtarget->hasSVE2p2() || Subtarget->hasSME2p2())">,
+    : Predicate<"Subtarget->hasSVE2p2() ||"
+                "(Subtarget->isStreaming() && Subtarget->hasSME2p2())">,
                 AssemblerPredicateWithAll<(any_of FeatureSME2p2, FeatureSVE2p2),
                 "sme2p2 or sve2p2">;
 def HasNonStreamingSVE2p2_or_SME2p2
     : Predicate<"(Subtarget->isSVEAvailable() && Subtarget->hasSVE2p2()) ||"
-                "(Subtarget->isSVEorStreamingSVEAvailable() && Subtarget->hasSME2p2())">,
+                "(Subtarget->isStreaming() && Subtarget->hasSME2p2())">,
                 AssemblerPredicateWithAll<(any_of FeatureSVE2p2, FeatureSME2p2),
                 "sme2p2 or sve2p2">;
 
diff --git a/llvm/test/CodeGen/AArch64/sve2p2-intrinsics.ll b/llvm/test/CodeGen/AArch64/sve2p2-intrinsics.ll
index 8d863dab7b47d..62a9cd15d3956 100644
--- a/llvm/test/CodeGen/AArch64/sve2p2-intrinsics.ll
+++ b/llvm/test/CodeGen/AArch64/sve2p2-intrinsics.ll
@@ -1,6 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve2p2 < %s | FileCheck %s --check-prefixes=CHECK
 ; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sme2p2 -force-streaming < %s | FileCheck %s --check-prefixes=CHECK
+; RUN: not --crash llc -mtriple=aarch64-linux-gnu -mattr=+sve,+sme2p2 < %s
 
 ;
 ; COMPACT
diff --git a/llvm/test/CodeGen/AArch64/zeroing-forms-ext.ll b/llvm/test/CodeGen/AArch64/zeroing-forms-ext.ll
index 20a5475706c9c..e19a9527532c8 100644
--- a/llvm/test/CodeGen/AArch64/zeroing-forms-ext.ll
+++ b/llvm/test/CodeGen/AArch64/zeroing-forms-ext.ll
@@ -1,9 +1,12 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mattr=+sve    < %s | FileCheck %s -check-prefixes=CHECK,SVE
-; RUN: llc -mattr=+sve2p2 < %s | FileCheck %s -check-prefix CHECK-2p2
+; RUN: llc -mattr=+sve2p2 < %s | FileCheck %s -check-prefix=CHECK-2p2
 
 ; RUN: llc -mattr=+sme    -force-streaming < %s | FileCheck %s -check-prefixes=CHECK,STREAMING-SVE
-; RUN: llc -mattr=+sme2p2 -force-streaming < %s | FileCheck %s -check-prefix CHECK-2p2
+; RUN: llc -mattr=+sme2p2 -force-streaming < %s | FileCheck %s -check-prefix=CHECK-2p2
+
+; SME2p2 instructions are only valid in streaming mode
+; RUN: llc -mattr=+sve,+sme2p2 < %s | FileCheck %s -check-prefixes=CHECK,SVE
 
 target triple = "aarch64-linux"