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[AArch64] Improve loop unrolling performance on Cavium T99

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This patch improves performance on Cavium T99 as shown here (libquantum 0.2.4):

https://docs.google.com/spreadsheets/d/1Lo1o2E1NjrpkwS7DvYYWsiVvPdd93h7KBaqeptMrZPY/edit?usp=sharing

By increasing the LoopMicroOpsBufferSize in the Cavium T99 Scheduler file,
loop unrolling becomes more aggressive. This helps performance on T99.

Test case included.

Patch by Stefan Teleman

Differential Revision: https://reviews.llvm.org/D40695 

llvm-svn: 320272
This commit is contained in:
Joel Jones 2017-12-09 23:59:55 +00:00
parent 1e07e1ec5a
commit 11c2f5c876
2 changed files with 125 additions and 1 deletions
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2
lib/Target/AArch64/AArch64SchedThunderX2T99.td
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@ -22,7 +22,7 @@ def ThunderX2T99Model : SchedMachineModel {
let LoadLatency = 4; // Optimistic load latency.
let MispredictPenalty = 12; // Extra cycles for mispredicted branch.
// Determined via a mix of micro-arch details and experimentation.
let LoopMicroOpBufferSize = 32;
let LoopMicroOpBufferSize = 128;
let PostRAScheduler = 1; // Using PostRA sched.
let CompleteModel = 1;

124
test/CodeGen/AArch64/loop-micro-op-buffer-size-t99.ll Normal file
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@ -0,0 +1,124 @@
; REQUIRES: asserts
; RUN: opt -mcpu=thunderx2t99 -loop-unroll --debug-only=loop-unroll -S -unroll-allow-partial < %s 2>&1 | FileCheck %s
target triple = "aarch64-unknown-linux-gnu"
; CHECK: Loop Unroll: F[foo] Loop %loop.2.header
; CHECK: Loop Size = 19
; CHECK: Trip Count = 512
; CHECK: Trip Multiple = 512
; CHECK: UNROLLING loop %loop.2.header by 4 with a breakout at trip 0
; CHECK: Merging:
; CHECK: Loop Unroll: F[foo] Loop %loop.header
; CHECK: Loop Size = 18
; CHECK: Trip Count = 512
; CHECK: Trip Multiple = 512
; CHECK: UNROLLING loop %loop.header by 4 with a breakout at trip 0
; CHECK: Merging:
; CHECK: %counter = phi i32 [ 0, %entry ], [ %inc.3, %loop.inc.3 ]
; CHECK: %val = add nuw nsw i32 %counter, 5
; CHECK: %val1 = add nuw nsw i32 %counter, 6
; CHECK: %val2 = add nuw nsw i32 %counter, 7
; CHECK: %val3 = add nuw nsw i32 %counter, 8
; CHECK: %val4 = add nuw nsw i32 %counter, 9
; CHECK: %val5 = add nuw nsw i32 %counter, 10
; CHECK-NOT: %val = add i32 %counter, 5
; CHECK-NOT: %val = add i32 %counter, 6
; CHECK-NOT: %val = add i32 %counter, 7
; CHECK-NOT: %val = add i32 %counter, 8
; CHECK-NOT: %val = add i32 %counter, 9
; CHECK-NOT: %val = add i32 %counter, 10
; CHECK: %counter.2 = phi i32 [ 0, %exit.0 ], [ %inc.2.3, %loop.2.inc.3 ]
define void @foo(i32 * %out) {
entry:
%0 = alloca [1024 x i32]
%x0 = alloca [1024 x i32]
%x01 = alloca [1024 x i32]
%x02 = alloca [1024 x i32]
%x03 = alloca [1024 x i32]
%x04 = alloca [1024 x i32]
%x05 = alloca [1024 x i32]
%x06 = alloca [1024 x i32]
br label %loop.header
loop.header:
%counter = phi i32 [0, %entry], [%inc, %loop.inc]
br label %loop.body
loop.body:
%ptr = getelementptr [1024 x i32], [1024 x i32]* %0, i32 0, i32 %counter
store i32 %counter, i32* %ptr
%val = add i32 %counter, 5
%xptr = getelementptr [1024 x i32], [1024 x i32]* %x0, i32 0, i32 %counter
store i32 %val, i32* %xptr
%val1 = add i32 %counter, 6
%xptr1 = getelementptr [1024 x i32], [1024 x i32]* %x01, i32 0, i32 %counter
store i32 %val1, i32* %xptr1
%val2 = add i32 %counter, 7
%xptr2 = getelementptr [1024 x i32], [1024 x i32]* %x02, i32 0, i32 %counter
store i32 %val2, i32* %xptr2
%val3 = add i32 %counter, 8
%xptr3 = getelementptr [1024 x i32], [1024 x i32]* %x03, i32 0, i32 %counter
store i32 %val3, i32* %xptr3
%val4 = add i32 %counter, 9
%xptr4 = getelementptr [1024 x i32], [1024 x i32]* %x04, i32 0, i32 %counter
store i32 %val4, i32* %xptr4
%val5 = add i32 %counter, 10
%xptr5 = getelementptr [1024 x i32], [1024 x i32]* %x05, i32 0, i32 %counter
store i32 %val5, i32* %xptr5
br label %loop.inc
loop.inc:
%inc = add i32 %counter, 2
%1 = icmp sge i32 %inc, 1023
br i1 %1, label %exit.0, label %loop.header
exit.0:
%2 = getelementptr [1024 x i32], [1024 x i32]* %0, i32 0, i32 5
%3 = load i32, i32* %2
store i32 %3, i32 * %out
br label %loop.2.header
loop.2.header:
%counter.2 = phi i32 [0, %exit.0], [%inc.2, %loop.2.inc]
br label %loop.2.body
loop.2.body:
%ptr.2 = getelementptr [1024 x i32], [1024 x i32]* %0, i32 0, i32 %counter.2
store i32 %counter.2, i32* %ptr.2
%val.2 = add i32 %counter.2, 5
%xptr.2 = getelementptr [1024 x i32], [1024 x i32]* %x0, i32 0, i32 %counter.2
store i32 %val.2, i32* %xptr.2
%val1.2 = add i32 %counter.2, 6
%xptr1.2 = getelementptr [1024 x i32], [1024 x i32]* %x01, i32 0, i32 %counter.2
store i32 %val1, i32* %xptr1.2
%val2.2 = add i32 %counter.2, 7
%xptr2.2 = getelementptr [1024 x i32], [1024 x i32]* %x02, i32 0, i32 %counter.2
store i32 %val2, i32* %xptr2.2
%val3.2 = add i32 %counter.2, 8
%xptr3.2 = getelementptr [1024 x i32], [1024 x i32]* %x03, i32 0, i32 %counter.2
store i32 %val3.2, i32* %xptr3.2
%val4.2 = add i32 %counter.2, 9
%xptr4.2 = getelementptr [1024 x i32], [1024 x i32]* %x04, i32 0, i32 %counter.2
store i32 %val4.2, i32* %xptr4.2
%val5.2 = add i32 %counter.2, 10
%xptr5.2 = getelementptr [1024 x i32], [1024 x i32]* %x05, i32 0, i32 %counter.2
store i32 %val5.2, i32* %xptr5.2
%xptr6.2 = getelementptr [1024 x i32], [1024 x i32]* %x06, i32 0, i32 %counter.2
store i32 %val5.2, i32* %xptr6.2
br label %loop.2.inc
loop.2.inc:
%inc.2 = add i32 %counter.2, 2
%4 = icmp sge i32 %inc.2, 1023
br i1 %4, label %exit.2, label %loop.2.header
exit.2:
%x2 = getelementptr [1024 x i32], [1024 x i32]* %0, i32 0, i32 6
%x3 = load i32, i32* %x2
%out2 = getelementptr i32, i32 * %out, i32 1
store i32 %3, i32 * %out2
ret void
}