[RISCV][MC] MC layer support for the experimental zalasr extension (#79911)

This PR implements experimental support for the RISC-V Atomic
Load-Acquire and Store-Release Extension (Zalasr). It has been approved
to be pursued as a fast track extension
(https://lists.riscv.org/g/tech-unprivileged/topic/arc_architecture_review/101951698),
but has not yet been approved by ARC or ratified. See
https://github.com/mehnadnerd/riscv-zalasr for draft spec.

---------

Co-authored-by: brs <turtwig@utexas.edu>
Co-authored-by: Philip Reames <preames@rivosinc.com>

13 files changed, 265 insertions, 0 deletions

diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
index 2361c83..35d112b 100644
--- a/clang/test/Preprocessor/riscv-target-features.c
+++ b/clang/test/Preprocessor/riscv-target-features.c
@@ -144,6 +144,7 @@
 
 // CHECK-NOT: __riscv_zaamo {{.*$}}
 // CHECK-NOT: __riscv_zacas {{.*$}}
+// CHECK-NOT: __riscv_zalasr {{.*$}}
 // CHECK-NOT: __riscv_zalrsc {{.*$}}
 // CHECK-NOT: __riscv_zcmop {{.*$}}
 // CHECK-NOT: __riscv_zfbfmin {{.*$}}
@@ -1334,6 +1335,14 @@
 // CHECK-ZACAS-EXT: __riscv_zacas 1000000{{$}}
 
 // RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_zalasr0p1 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZALASR-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_zalasr0p1 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZALASR-EXT %s
+// CHECK-ZALASR-EXT: __riscv_zalasr 1000{{$}}
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
 // RUN:   -march=rv32i_zalrsc0p2 -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZALRSC-EXT %s
 // RUN: %clang --target=riscv64 -menable-experimental-extensions \
diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index 5caf2fe..a957a8d 100644
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -232,6 +232,9 @@ The primary goal of experimental support is to assist in the process of ratifica
 ``experimental-zacas``
   LLVM implements the `1.0-rc1 draft specification <https://github.com/riscv/riscv-zacas/releases/tag/v1.0-rc1>`_.
 
+``experimental-zalasr``
+  LLVM implements the `0.0.5 draft specification <https://github.com/mehnadnerd/riscv-zalasr>`_.
+
 ``experimental-zfbfmin``, ``experimental-zvfbfmin``, ``experimental-zvfbfwma``
   LLVM implements assembler support for the `1.0.0-rc2 specification <https://github.com/riscv/riscv-bfloat16/releases/tag/v59042fc71c31a9bcb2f1957621c960ed36fac401>`_.
 
diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
index 0ae1fc0..8f31b0f 100644
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -197,6 +197,7 @@ static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
     {"zaamo", {0, 2}},
     {"zabha", {1, 0}},
     {"zacas", {1, 0}},
+    {"zalasr", {0, 1}},
     {"zalrsc", {0, 2}},
 
     {"zcmop", {0, 2}},
diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
index 6b7bf48..6f87eae 100644
--- a/llvm/lib/Target/RISCV/RISCVFeatures.td
+++ b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -192,6 +192,13 @@ def HasStdExtZacas : Predicate<"Subtarget->hasStdExtZacas()">,
                          "'Zacas' (Atomic Compare-And-Swap Instructions)">;
 def NoStdExtZacas : Predicate<"!Subtarget->hasStdExtZacas()">;
 
+def FeatureStdExtZalasr
+    : SubtargetFeature<"experimental-zalasr", "HasStdExtZalasr", "true",
+                       "'Zalasr' (Load-Acquire and Store-Release Instructions)">;
+def HasStdExtZalasr : Predicate<"Subtarget->hasStdExtZalasr()">,
+                      AssemblerPredicate<(all_of FeatureStdExtZalasr),
+                          "'Zalasr' (Load-Acquire and Store-Release Instructions)">;
+
 def FeatureStdExtZalrsc
     : SubtargetFeature<"experimental-zalrsc", "HasStdExtZalrsc", "true",
                        "'Zalrsc' (Load-Reserved/Store-Conditional)">;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
index 67f73b2..12c1806 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -2146,6 +2146,7 @@ include "RISCVInstrInfoM.td"
 // Atomic
 include "RISCVInstrInfoA.td"
 include "RISCVInstrInfoZa.td"
+include "RISCVInstrInfoZalasr.td"
 
 // Scalar FP
 include "RISCVInstrInfoF.td"
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZalasr.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZalasr.td
new file mode 100644
index 0000000..fd5bdea
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZalasr.td
@@ -0,0 +1,59 @@
+//===-- RISCVInstrInfoZalasr.td  ---------------------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file describes the RISC-V instructions from the Zalasr (Load-Acquire
+// and Store-Release) extension
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Instruction class templates
+//===----------------------------------------------------------------------===//
+
+let hasSideEffects = 0, mayLoad = 1, mayStore = 0 in
+class LAQ_r<bit aq, bit rl, bits<3> funct3, string opcodestr>
+    : RVInstRAtomic<0b00110, aq, rl, funct3, OPC_AMO,
+                    (outs GPR:$rd), (ins GPRMemZeroOffset:$rs1),
+                    opcodestr, "$rd, $rs1"> {
+  let rs2 = 0;
+}
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 1 in
+class SRL_r<bit aq, bit rl, bits<3> funct3, string opcodestr>
+    : RVInstRAtomic<0b00111, aq, rl, funct3, OPC_AMO,
+                    (outs ), (ins GPRMemZeroOffset:$rs1, GPR:$rs2),
+                    opcodestr, "$rs2, $rs1"> {
+  let rd = 0;
+}
+multiclass LAQ_r_aq_rl<bits<3> funct3, string opcodestr> {
+  def _AQ    : LAQ_r<1, 0, funct3, opcodestr # ".aq">;
+  def _AQ_RL : LAQ_r<1, 1, funct3, opcodestr # ".aqrl">;
+}
+
+multiclass SRL_r_aq_rl<bits<3> funct3, string opcodestr> {
+  def _RL    : SRL_r<0, 1, funct3, opcodestr # ".rl">;
+  def _AQ_RL : SRL_r<1, 1, funct3, opcodestr # ".aqrl">;
+}
+
+//===----------------------------------------------------------------------===//
+// Instructions
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasStdExtZalasr] in {
+defm LB : LAQ_r_aq_rl<0b000, "lb">;
+defm LH : LAQ_r_aq_rl<0b001, "lh">;
+defm LW : LAQ_r_aq_rl<0b010, "lw">;
+defm SB : SRL_r_aq_rl<0b000, "sb">;
+defm SH : SRL_r_aq_rl<0b001, "sh">;
+defm SW : SRL_r_aq_rl<0b010, "sw">;
+} // Predicates = [HasStdExtZalasr]
+
+let Predicates = [HasStdExtZalasr, IsRV64] in {
+defm LD : LAQ_r_aq_rl<0b011, "ld">;
+defm SD : SRL_r_aq_rl<0b011, "sd">;
+} // Predicates = [HasStdExtZalasr, IsRV64]
diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
index 8c5d33d..f7b53d6 100644
--- a/llvm/test/CodeGen/RISCV/attributes.ll
+++ b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -95,6 +95,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zvfbfwma %s -o - | FileCheck --check-prefixes=CHECK,RV32ZVFBFWMA %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zaamo %s -o - | FileCheck --check-prefix=RV32ZAAMO %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zacas %s -o - | FileCheck --check-prefix=RV32ZACAS %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zalasr %s -o - | FileCheck --check-prefix=RV32ZALASR %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zalrsc %s -o - | FileCheck --check-prefix=RV32ZALRSC %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV32ZICFILP %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zabha %s -o - | FileCheck --check-prefix=RV32ZABHA %s
@@ -200,6 +201,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zvfbfwma %s -o - | FileCheck --check-prefixes=CHECK,RV64ZVFBFWMA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zaamo %s -o - | FileCheck --check-prefix=RV64ZAAMO %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zacas %s -o - | FileCheck --check-prefix=RV64ZACAS %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zalasr %s -o - | FileCheck --check-prefix=RV64ZALASR %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zalrsc %s -o - | FileCheck --check-prefix=RV64ZALRSC %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV64ZICFILP %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zabha %s -o - | FileCheck --check-prefix=RV64ZABHA %s
@@ -300,6 +302,7 @@
 ; RV32ZVFBFWMA: .attribute 5, "rv32i2p1_f2p2_zicsr2p0_zfbfmin1p0_zve32f1p0_zve32x1p0_zvfbfmin1p0_zvfbfwma1p0_zvl32b1p0"
 ; RV32ZAAMO: .attribute 5, "rv32i2p1_zaamo0p2"
 ; RV32ZACAS: .attribute 5, "rv32i2p1_a2p1_zacas1p0"
+; RV32ZALASR: .attribute 5, "rv32i2p1_zalasr0p1"
 ; RV32ZALRSC: .attribute 5, "rv32i2p1_zalrsc0p2"
 ; RV32ZICFILP: .attribute 5, "rv32i2p1_zicfilp0p4"
 ; RV32ZABHA: .attribute 5, "rv32i2p1_a2p1_zabha1p0"
@@ -404,6 +407,7 @@
 ; RV64ZVFBFWMA: .attribute 5, "rv64i2p1_f2p2_zicsr2p0_zfbfmin1p0_zve32f1p0_zve32x1p0_zvfbfmin1p0_zvfbfwma1p0_zvl32b1p0"
 ; RV64ZAAMO: .attribute 5, "rv64i2p1_zaamo0p2"
 ; RV64ZACAS: .attribute 5, "rv64i2p1_a2p1_zacas1p0"
+; RV64ZALASR: .attribute 5, "rv64i2p1_zalasr0p1"
 ; RV64ZALRSC: .attribute 5, "rv64i2p1_zalrsc0p2"
 ; RV64ZICFILP: .attribute 5, "rv64i2p1_zicfilp0p4"
 ; RV64ZABHA: .attribute 5, "rv64i2p1_a2p1_zabha1p0"
diff --git a/llvm/test/MC/RISCV/attribute-arch.s b/llvm/test/MC/RISCV/attribute-arch.s
index 5f9a7ca..8810ca67 100644
--- a/llvm/test/MC/RISCV/attribute-arch.s
+++ b/llvm/test/MC/RISCV/attribute-arch.s
@@ -309,6 +309,9 @@
 .attribute arch, "rv32izacas1p0"
 # CHECK: attribute      5, "rv32i2p1_a2p1_zacas1p0"
 
+.attribute arch, "rv32izalasr0p1"
+# CHECK: attribute      5, "rv32i2p1_zalasr0p1"
+
 .attribute arch, "rv32i_xcvalu"
 # CHECK: attribute      5, "rv32i2p1_xcvalu1p0"
 
diff --git a/llvm/test/MC/RISCV/rv32zalasr-invalid.s b/llvm/test/MC/RISCV/rv32zalasr-invalid.s
new file mode 100644
index 0000000..3731c85
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv32zalasr-invalid.s
@@ -0,0 +1,40 @@
+# RUN: not llvm-mc -triple riscv32 -mattr=+experimental-zalasr < %s 2>&1 | FileCheck -check-prefixes=CHECK %s
+
+# CHECK: error: instruction requires the following: RV64I Base Instruction Set{{$}}
+ld.aq a1, (t0)
+
+# CHECK: error: instruction requires the following: RV64I Base Instruction Set{{$}}
+ld.aqrl a1, (t0)
+
+# CHECK: error: instruction requires the following: RV64I Base Instruction Set{{$}}
+sd.rl a1, (t0)
+
+# CHECK: error: instruction requires the following: RV64I Base Instruction Set{{$}}
+sd.aqrl a1, (t0)
+
+# CHECK: error: unrecognized instruction mnemonic
+lw. a1, (t0)
+
+# CHECK: error: unrecognized instruction mnemonic
+lw.rl t3, 0(t5)
+
+# CHECK: error: unrecognized instruction mnemonic
+lh.rlaq t4, (t6)
+
+# CHECK: error: unrecognized instruction mnemonic
+sb. a1, (t0)
+
+# CHECK: error: unrecognized instruction mnemonic
+sh.aq t3, 0(t5)
+
+# CHECK: error: unrecognized instruction mnemonic
+sh.rlaq t4, (t6)
+
+# CHECK: error: optional integer offset must be 0
+lw.aq zero, 1(a0)
+
+# CHECK: error: optional integer offset must be 0
+sw.rl t1, 2(s0)
+
+# CHECK: error: optional integer offset must be 0
+sb.aqrl sp, 3(s2)
diff --git a/llvm/test/MC/RISCV/rv32zalasr-valid.s b/llvm/test/MC/RISCV/rv32zalasr-valid.s
new file mode 100644
index 0000000..7b2668b
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv32zalasr-valid.s
@@ -0,0 +1,78 @@
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-zalasr -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+experimental-zalasr < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zalasr -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zalasr -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zalasr < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zalasr -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+#
+# RUN: not llvm-mc -triple riscv32 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck --check-prefixes=CHECK-NO-EXT %s
+# RUN: not llvm-mc -triple riscv64 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck --check-prefixes=CHECK-NO-EXT %s
+
+# CHECK-ASM-AND-OBJ: lb.aq t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x03,0x05,0x34]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lb.aq t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: lh.aq t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x13,0x05,0x34]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lh.aq t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: lw.aq t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x23,0x05,0x34]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lw.aq t1, (a0)
+
+# CHECK-ASM-AND-OBJ: lb.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x03,0x05,0x36]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lb.aqrl t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: lh.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x13,0x05,0x36]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lh.aqrl t1, (a0)
+
+# CHECK-ASM-AND-OBJ: lw.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x23,0x05,0x36]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+lw.aqrl t1, (a0)
+
+
+# CHECK-ASM-AND-OBJ: sb.rl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x00,0x65,0x3a]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sb.rl t1, (a0)
+
+# CHECK-ASM-AND-OBJ: sh.rl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x10,0x65,0x3a]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sh.rl t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: sw.rl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x20,0x65,0x3a]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sw.rl t1, (a0)
+
+# CHECK-ASM-AND-OBJ: sb.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x00,0x65,0x3e]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sb.aqrl t1, (a0)
+
+# CHECK-ASM-AND-OBJ: sh.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x10,0x65,0x3e]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sh.aqrl t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: sw.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x20,0x65,0x3e]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sw.aqrl t1, 0(a0)
diff --git a/llvm/test/MC/RISCV/rv64zalasr-invalid.s b/llvm/test/MC/RISCV/rv64zalasr-invalid.s
new file mode 100644
index 0000000..032c0c00
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv64zalasr-invalid.s
@@ -0,0 +1,28 @@
+# RUN: not llvm-mc -triple riscv64 -mattr=+experimental-zalasr < %s 2>&1 | FileCheck -check-prefixes=CHECK %s
+
+# CHECK: error: unrecognized instruction mnemonic
+lw. a1, (t0)
+
+# CHECK: error: unrecognized instruction mnemonic
+lw.rl t3, 0(t5)
+
+# CHECK: error: unrecognized instruction mnemonic
+lh.rlaq t4, (t6)
+
+# CHECK: error: unrecognized instruction mnemonic
+sb. a1, (t0)
+
+# CHECK: error: unrecognized instruction mnemonic
+sh.aq t3, 0(t5)
+
+# CHECK: error: unrecognized instruction mnemonic
+sh.rlaq t4, (t6)
+
+# CHECK: error: optional integer offset must be 0
+lw.aq zero, 1(a0)
+
+# CHECK: error: optional integer offset must be 0
+sw.rl t1, 2(s0)
+
+# CHECK: error: optional integer offset must be 0
+sb.aqrl sp, 3(s2)
diff --git a/llvm/test/MC/RISCV/rv64zalasr-valid.s b/llvm/test/MC/RISCV/rv64zalasr-valid.s
new file mode 100644
index 0000000..2f1e381
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv64zalasr-valid.s
@@ -0,0 +1,31 @@
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zalasr -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zalasr < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zalasr -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+#
+# RUN: not llvm-mc -triple riscv64 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck --check-prefixes=CHECK-NO-EXT %s
+
+
+# CHECK-ASM-AND-OBJ: ld.aq t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x33,0x05,0x34]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+ld.aq t1, (a0)
+
+# CHECK-ASM-AND-OBJ: ld.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x33,0x05,0x36]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+ld.aqrl t1, 0(a0)
+
+
+# CHECK-ASM-AND-OBJ: sd.rl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x30,0x65,0x3a]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sd.rl t1, 0(a0)
+
+# CHECK-ASM-AND-OBJ: sd.aqrl t1, (a0)
+# CHECK-ASM: encoding: [0x2f,0x30,0x65,0x3e]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zalasr' (Load-Acquire and Store-Release Instructions){{$}}
+sd.aqrl t1, (a0)
diff --git a/llvm/unittests/Support/RISCVISAInfoTest.cpp b/llvm/unittests/Support/RISCVISAInfoTest.cpp
index 4cd9574..66e10bf 100644
--- a/llvm/unittests/Support/RISCVISAInfoTest.cpp
+++ b/llvm/unittests/Support/RISCVISAInfoTest.cpp
@@ -857,6 +857,7 @@ Experimental extensions
     zaamo               0.2
     zabha               1.0
     zacas               1.0
+    zalasr              0.1
     zalrsc              0.2
     zfbfmin             1.0
     zcmop               0.2