[llvm] 43a9ec2 - [AArch64][SME] Instcombine `llvm.aarch64.sme.in.streaming.mode()` (#147930)

[via llvm-commits]

Author: Benjamin Maxwell
Date: 2025-07-13T13:20:20+01:00
New Revision: 43a9ec2ecdf4aac8966e3b02e4e92c794f5b6a27

URL: https://github.com/llvm/llvm-project/commit/43a9ec2ecdf4aac8966e3b02e4e92c794f5b6a27
DIFF: https://github.com/llvm/llvm-project/commit/43a9ec2ecdf4aac8966e3b02e4e92c794f5b6a27.diff

LOG: [AArch64][SME] Instcombine `llvm.aarch64.sme.in.streaming.mode()` (#147930)

This can fold away in functions with known streaming modes.

Added: 
    llvm/test/Transforms/InstCombine/AArch64/aarch64-sme-in-streaming-mode.ll

Modified: 
    llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index c04cbc80bc5b6..392f1f6efa997 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -2723,6 +2723,16 @@ static std::optional<Instruction *> instCombineSVEUxt(InstCombiner &IC,
   return std::nullopt;
 }
 
+static std::optional<Instruction *>
+instCombineInStreamingMode(InstCombiner &IC, IntrinsicInst &II) {
+  SMEAttrs FnSMEAttrs(*II.getFunction());
+  bool IsStreaming = FnSMEAttrs.hasStreamingInterfaceOrBody();
+  if (IsStreaming || !FnSMEAttrs.hasStreamingCompatibleInterface())
+    return IC.replaceInstUsesWith(
+        II, ConstantInt::getBool(II.getType(), IsStreaming));
+  return std::nullopt;
+}
+
 std::optional<Instruction *>
 AArch64TTIImpl::instCombineIntrinsic(InstCombiner &IC,
                                      IntrinsicInst &II) const {
@@ -2828,6 +2838,8 @@ AArch64TTIImpl::instCombineIntrinsic(InstCombiner &IC,
     return instCombineSVEUxt(IC, II, 16);
   case Intrinsic::aarch64_sve_uxtw:
     return instCombineSVEUxt(IC, II, 32);
+  case Intrinsic::aarch64_sme_in_streaming_mode:
+    return instCombineInStreamingMode(IC, II);
   }
 
   return std::nullopt;

diff  --git a/llvm/test/Transforms/InstCombine/AArch64/aarch64-sme-in-streaming-mode.ll b/llvm/test/Transforms/InstCombine/AArch64/aarch64-sme-in-streaming-mode.ll
new file mode 100644
index 0000000000000..e8170ba3106a6
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/AArch64/aarch64-sme-in-streaming-mode.ll
@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=instcombine -mtriple aarch64 -mattr=+sme -S -o - < %s | FileCheck %s
+
+define i1 @test_in_streaming_mode_streaming_compatible() "aarch64_pstate_sm_compatible" {
+; CHECK-LABEL: define i1 @test_in_streaming_mode_streaming_compatible(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    [[SM:%.*]] = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+; CHECK-NEXT:    ret i1 [[SM]]
+;
+  %sm = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+  ret i1 %sm
+}
+
+define i1 @test_in_streaming_mode_streaming() "aarch64_pstate_sm_enabled" {
+; CHECK-LABEL: define i1 @test_in_streaming_mode_streaming(
+; CHECK-SAME: ) #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT:    ret i1 true
+;
+  %sm = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+  ret i1 %sm
+}
+
+define i1 @test_in_streaming_mode_streaming_compatible_streaming_body() "aarch64_pstate_sm_compatible" "aarch64_pstate_sm_body" {
+; CHECK-LABEL: define i1 @test_in_streaming_mode_streaming_compatible_streaming_body(
+; CHECK-SAME: ) #[[ATTR2:[0-9]+]] {
+; CHECK-NEXT:    ret i1 true
+;
+  %sm = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+  ret i1 %sm
+}
+
+define i1 @test_in_streaming_mode_streaming_body() "aarch64_pstate_sm_body" {
+; CHECK-LABEL: define i1 @test_in_streaming_mode_streaming_body(
+; CHECK-SAME: ) #[[ATTR3:[0-9]+]] {
+; CHECK-NEXT:    ret i1 true
+;
+  %sm = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+  ret i1 %sm
+}
+
+define i1 @test_in_streaming_mode_non_streaming() {
+; CHECK-LABEL: define i1 @test_in_streaming_mode_non_streaming(
+; CHECK-SAME: ) #[[ATTR4:[0-9]+]] {
+; CHECK-NEXT:    ret i1 false
+;
+  %sm = tail call i1 @llvm.aarch64.sme.in.streaming.mode()
+  ret i1 %sm
+}