From 24c37158060c1ab8ac13a6fb6517a5a6c906e079 Mon Sep 17 00:00:00 2001 From: Matt Arsenault Date: Fri, 25 Jul 2025 18:52:34 +0900 Subject: [PATCH] AMDGPU: Fix -amdgpu-mfma-vgpr-form flag on gfx908 This should be ignored since there are no VGPR forms. This makes it possible to flip the default for the flag to true. --- llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp | 14 +++++++++----- llvm/test/CodeGen/AMDGPU/gfx90a-enc.ll | 3 +++ 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp index f0be204cd9bdb..9a1448f1f95dc 100644 --- a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp +++ b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp @@ -81,11 +81,15 @@ SIMachineFunctionInfo::SIMachineFunctionInfo(const Function &F, PSInputAddr = AMDGPU::getInitialPSInputAddr(F); } - MayNeedAGPRs = ST.hasMAIInsts() && !MFMAVGPRForm; - if (!MFMAVGPRForm && ST.hasGFX90AInsts() && - ST.getMaxNumVGPRs(F) <= AMDGPU::VGPR_32RegClass.getNumRegs() && - !mayUseAGPRs(F)) - MayNeedAGPRs = false; // We will select all MAI with VGPR operands. + MayNeedAGPRs = ST.hasMAIInsts(); + if (ST.hasGFX90AInsts()) { + // FIXME: MayNeedAGPRs is a misnomer for how this is used. MFMA selection + // should be separated from availability of AGPRs + if (MFMAVGPRForm || + (ST.getMaxNumVGPRs(F) <= AMDGPU::VGPR_32RegClass.getNumRegs() && + !mayUseAGPRs(F))) + MayNeedAGPRs = false; // We will select all MAI with VGPR operands. + } if (AMDGPU::isChainCC(CC)) { // Chain functions don't receive an SP from their caller, but are free to diff --git a/llvm/test/CodeGen/AMDGPU/gfx90a-enc.ll b/llvm/test/CodeGen/AMDGPU/gfx90a-enc.ll index 99690e407d8da..fe8edd5d60912 100644 --- a/llvm/test/CodeGen/AMDGPU/gfx90a-enc.ll +++ b/llvm/test/CodeGen/AMDGPU/gfx90a-enc.ll @@ -1,4 +1,7 @@ ; RUN: llc -mtriple=amdgcn -mcpu=gfx908 -show-mc-encoding < %s | FileCheck -check-prefixes=GFX9,GFX908 %s + +; Make sure flag is ignored +; RUN: llc -mtriple=amdgcn -mcpu=gfx908 -amdgpu-mfma-vgpr-form=1 -show-mc-encoding < %s | FileCheck -check-prefixes=GFX9,GFX908 %s ; RUN: llc -mtriple=amdgcn -mcpu=gfx90a -show-mc-encoding < %s | FileCheck -check-prefixes=GFX9,GFX90A %s ; GFX9-DAG: buffer_load_format_xyzw v[{{[0-9:]+}}], v{{[0-9]+}}, s[{{[0-9:]+}}], 0 idxen ; encoding: