Reapply "[llvm-exegesis] Implement the loop repetition mode for AArch64" (#155423) #155589
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…64" (llvm#155423) This includes two minor fixes: - "Codegen" has been added to the LLVM_LINK_COMPONENTS for AArch64 to prevent a link error, - the test case has been made less strict or fragile by not checking the addresses.
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@llvm/pr-subscribers-tools-llvm-exegesis Author: Sjoerd Meijer (sjoerdmeijer) ChangesThis includes two minor fixes:
Full diff: https://github.com/llvm/llvm-project/pull/155589.diff 3 Files Affected:
diff --git a/llvm/test/tools/llvm-exegesis/AArch64/loop-register.s b/llvm/test/tools/llvm-exegesis/AArch64/loop-register.s
new file mode 100644
index 0000000000000..62040b26c8faf
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/AArch64/loop-register.s
@@ -0,0 +1,17 @@
+REQUIRES: aarch64-registered-target, asserts
+
+RUN: llvm-exegesis -mcpu=neoverse-v2 --use-dummy-perf-counters --mode=latency --debug-only=print-gen-assembly --opcode-name=ADDVv4i16v -repetition-mode=loop 2>&1 | FileCheck %s
+
+CHECK: str x19, [sp, #-16]!
+CHECK-NEXT: movi d[[REG:[0-9]+]], #0000000000000000
+CHECK-NEXT: mov x19, #10000
+CHECK-NEXT: nop
+CHECK-NEXT: nop
+CHECK-NEXT: nop
+CHECK-NEXT: nop
+CHECK-NEXT: nop
+CHECK-NEXT: addv h[[REG]], v[[REG]].4h
+CHECK-NEXT: subs x19, x19, #1
+CHECK-NEXT: b.ne #-8
+CHECK-NEXT: ldr x19, [sp], #16
+CHECK-NEXT: ret
diff --git a/llvm/tools/llvm-exegesis/lib/AArch64/CMakeLists.txt b/llvm/tools/llvm-exegesis/lib/AArch64/CMakeLists.txt
index 42f8fd30ac2bb..091215c18632d 100644
--- a/llvm/tools/llvm-exegesis/lib/AArch64/CMakeLists.txt
+++ b/llvm/tools/llvm-exegesis/lib/AArch64/CMakeLists.txt
@@ -5,6 +5,7 @@ include_directories(
set(LLVM_LINK_COMPONENTS
AArch64
+ CodeGen
CodeGenTypes
Core
Exegesis
diff --git a/llvm/tools/llvm-exegesis/lib/AArch64/Target.cpp b/llvm/tools/llvm-exegesis/lib/AArch64/Target.cpp
index 3a0021e3c132d..c4ad9ae201d4e 100644
--- a/llvm/tools/llvm-exegesis/lib/AArch64/Target.cpp
+++ b/llvm/tools/llvm-exegesis/lib/AArch64/Target.cpp
@@ -8,6 +8,7 @@
#include "../Target.h"
#include "AArch64.h"
#include "AArch64RegisterInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
#if defined(__aarch64__) && defined(__linux__)
#include <sys/prctl.h> // For PR_PAC_* constants
@@ -109,6 +110,10 @@ static MCInst loadFPImmediate(MCRegister Reg, unsigned RegBitWidth,
namespace {
+// Use X19 as the loop counter register since it's a callee-saved register
+// that's available for temporary use.
+constexpr const MCPhysReg kDefaultLoopCounterReg = AArch64::X19;
+
class ExegesisAArch64Target : public ExegesisTarget {
public:
ExegesisAArch64Target()
@@ -141,6 +146,31 @@ class ExegesisAArch64Target : public ExegesisTarget {
errs() << "setRegTo is not implemented, results will be unreliable\n";
return {};
}
+ MCRegister getDefaultLoopCounterRegister(const Triple &) const override {
+ return kDefaultLoopCounterReg;
+ }
+
+ void decrementLoopCounterAndJump(MachineBasicBlock &MBB,
+ MachineBasicBlock &TargetMBB,
+ const MCInstrInfo &MII,
+ MCRegister LoopRegister) const override {
+ // subs LoopRegister, LoopRegister, #1
+ BuildMI(&MBB, DebugLoc(), MII.get(AArch64::SUBSXri))
+ .addDef(LoopRegister)
+ .addUse(LoopRegister)
+ .addImm(1) // Subtract 1
+ .addImm(0); // No shift amount
+ // b.ne TargetMBB
+ BuildMI(&MBB, DebugLoc(), MII.get(AArch64::Bcc))
+ .addImm(AArch64CC::NE)
+ .addMBB(&TargetMBB);
+ }
+
+ // Registers that should not be selected for use in snippets.
+ const MCPhysReg UnavailableRegisters[1] = {kDefaultLoopCounterReg};
+ ArrayRef<MCPhysReg> getUnavailableRegisters() const override {
+ return UnavailableRegisters;
+ }
bool matchesArch(Triple::ArchType Arch) const override {
return Arch == Triple::aarch64 || Arch == Triple::aarch64_be;
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/23307 Here is the relevant piece of the build log for the reference |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/65/builds/21839 Here is the relevant piece of the build log for the reference |
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This includes two minor fixes: