From ad34447062ccf633b2d60ce6937355a900801a8c Mon Sep 17 00:00:00 2001 From: Sjoerd Meijer Date: Mon, 15 Sep 2025 03:44:26 -0700 Subject: [PATCH] Reapply "[llvm-exegesis] Exclude loads/stores from aliasing instruction set" (#156735) Move the mayLoad/mayStore checks out of hasMemoryOperands; there are instructions with these properties that don't have operands. --- .../test/tools/llvm-exegesis/AArch64/no-aliasing-ld-str.s | 8 ++++++++ llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp | 6 ++++++ 2 files changed, 14 insertions(+) create mode 100644 llvm/test/tools/llvm-exegesis/AArch64/no-aliasing-ld-str.s diff --git a/llvm/test/tools/llvm-exegesis/AArch64/no-aliasing-ld-str.s b/llvm/test/tools/llvm-exegesis/AArch64/no-aliasing-ld-str.s new file mode 100644 index 0000000000000..65e1203bb275d --- /dev/null +++ b/llvm/test/tools/llvm-exegesis/AArch64/no-aliasing-ld-str.s @@ -0,0 +1,8 @@ +REQUIRES: aarch64-registered-target + +RUN: llvm-exegesis -mtriple=aarch64 -mcpu=neoverse-v2 -mode=latency --dump-object-to-disk=%d --opcode-name=FMOVWSr --benchmark-phase=assemble-measured-code 2>&1 +RUN: llvm-objdump -d %d > %t.s +RUN: FileCheck %s < %t.s + +CHECK-NOT: ld{{[1-4]}} +CHECK-NOT: st{{[1-4]}} diff --git a/llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp b/llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp index bdfc93e22273b..707e6ee2d434b 100644 --- a/llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp +++ b/llvm/tools/llvm-exegesis/lib/SerialSnippetGenerator.cpp @@ -57,6 +57,12 @@ computeAliasingInstructions(const LLVMState &State, const Instruction *Instr, continue; if (OtherInstr.hasMemoryOperands()) continue; + // Filtering out loads/stores might belong in hasMemoryOperands(), but that + // complicates things as there are instructions with may load/store that + // don't have operands (e.g. X86's CLUI instruction). So, it's easier to + // filter them out here. + if (OtherInstr.Description.mayLoad() || OtherInstr.Description.mayStore()) + continue; if (!ET.allowAsBackToBack(OtherInstr)) continue; if (Instr->hasAliasingRegistersThrough(OtherInstr, ForbiddenRegisters))