From 479d45f82d07e90504419808be5ca6063744cc18 Mon Sep 17 00:00:00 2001 From: Stanislav Mekhanoshin Date: Wed, 15 Feb 2017 01:03:59 +0000 Subject: [PATCH] [AMDGPU] Fix MaxWorkGroupsPerCU for large workgroups This patch corrects the maximum workgroups per CU if we have big workgroups (more than 128). This calculation contributes to the occupancy calculation in respect to LDS size. Differential Revision: https://reviews.llvm.org/D29974 llvm-svn: 295134 --- lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp | 6 +++++- test/CodeGen/AMDGPU/large-work-group-promote-alloca.ll | 6 ++++-- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp b/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp index 02e47afeb91..0a1ab73d8dc 100644 --- a/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp +++ b/lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp @@ -151,7 +151,11 @@ unsigned getMaxWorkGroupsPerCU(const FeatureBitset &Features, unsigned FlatWorkGroupSize) { if (!Features.test(FeatureGCN)) return 8; - return getWavesPerWorkGroup(Features, FlatWorkGroupSize) == 1 ? 40 : 16; + unsigned N = getWavesPerWorkGroup(Features, FlatWorkGroupSize); + if (N == 1) + return 40; + N = 40 / N; + return std::min(N, 16u); } unsigned getMaxWavesPerCU(const FeatureBitset &Features) { diff --git a/test/CodeGen/AMDGPU/large-work-group-promote-alloca.ll b/test/CodeGen/AMDGPU/large-work-group-promote-alloca.ll index 71d21b120f0..93b33736b2a 100644 --- a/test/CodeGen/AMDGPU/large-work-group-promote-alloca.ll +++ b/test/CodeGen/AMDGPU/large-work-group-promote-alloca.ll @@ -69,7 +69,8 @@ entry: } ; ALL-LABEL: @occupancy_0( -; ALL: alloca [5 x i32] +; CI-NOT: alloca [5 x i32] +; SI: alloca [5 x i32] define void @occupancy_0(i32 addrspace(1)* nocapture %out, i32 addrspace(1)* nocapture %in) #3 { entry: %stack = alloca [5 x i32], align 4 @@ -91,7 +92,8 @@ entry: } ; ALL-LABEL: @occupancy_max( -; ALL: alloca [5 x i32] +; CI-NOT: alloca [5 x i32] +; SI: alloca [5 x i32] define void @occupancy_max(i32 addrspace(1)* nocapture %out, i32 addrspace(1)* nocapture %in) #4 { entry: %stack = alloca [5 x i32], align 4