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822bc4e4d3
Increase threshold to unroll a loop which contains an "if" statement whose condition defined by a PHI belonging to the loop. This may help to eliminate if region and potentially even PHI itself, saving on both divergence and registers used for the PHI. Add a small bonus for each of such "if" statements. Differential Revision: https://reviews.llvm.org/D31693 llvm-svn: 299779
101 lines
2.8 KiB
LLVM
101 lines
2.8 KiB
LLVM
; RUN: opt -mtriple=amdgcn-- -loop-unroll -simplifycfg -sroa %s -S -o - | FileCheck %s
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; RUN: opt -mtriple=r600-- -loop-unroll -simplifycfg -sroa %s -S -o - | FileCheck %s
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; This test contains a simple loop that initializes an array declared in
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; private memory. We want to make sure these kinds of loops are always
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; unrolled, because private memory is slow.
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; CHECK-LABEL: @private_memory
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; CHECK-NOT: alloca
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; CHECK: store i32 5, i32 addrspace(1)* %out
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define amdgpu_kernel void @private_memory(i32 addrspace(1)* %out) {
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entry:
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%0 = alloca [32 x i32]
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br label %loop.header
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loop.header:
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%counter = phi i32 [0, %entry], [%inc, %loop.inc]
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br label %loop.body
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loop.body:
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%ptr = getelementptr [32 x i32], [32 x i32]* %0, i32 0, i32 %counter
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store i32 %counter, i32* %ptr
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br label %loop.inc
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loop.inc:
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%inc = add i32 %counter, 1
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%1 = icmp sge i32 %counter, 32
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br i1 %1, label %exit, label %loop.header
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exit:
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%2 = getelementptr [32 x i32], [32 x i32]* %0, i32 0, i32 5
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%3 = load i32, i32* %2
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store i32 %3, i32 addrspace(1)* %out
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ret void
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}
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; Check that loop is unrolled for local memory references
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; CHECK-LABEL: @local_memory
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; CHECK: getelementptr i32, i32 addrspace(1)* %out, i32 128
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; CHECK-NEXT: store
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; CHECK-NEXT: ret
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define amdgpu_kernel void @local_memory(i32 addrspace(1)* %out, i32 addrspace(3)* %lds) {
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entry:
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br label %loop.header
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loop.header:
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%counter = phi i32 [0, %entry], [%inc, %loop.inc]
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br label %loop.body
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loop.body:
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%ptr_lds = getelementptr i32, i32 addrspace(3)* %lds, i32 %counter
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%val = load i32, i32 addrspace(3)* %ptr_lds
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%ptr_out = getelementptr i32, i32 addrspace(1)* %out, i32 %counter
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store i32 %val, i32 addrspace(1)* %ptr_out
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br label %loop.inc
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loop.inc:
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%inc = add i32 %counter, 1
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%cond = icmp sge i32 %counter, 128
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br i1 %cond, label %exit, label %loop.header
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exit:
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ret void
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}
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; Check that a loop with if inside completely unrolled to eliminate phi and if
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; CHECK-LABEL: @unroll_for_if
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; CHECK: entry:
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; CHECK-NEXT: getelementptr
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; CHECK-NEXT: store
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; CHECK-NEXT: getelementptr
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; CHECK-NEXT: store
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; CHECK-NOT: br
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define amdgpu_kernel void @unroll_for_if(i32* %a) {
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entry:
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br label %for.body
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for.body: ; preds = %entry, %for.inc
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%i1 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%and = and i32 %i1, 1
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%tobool = icmp eq i32 %and, 0
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br i1 %tobool, label %for.inc, label %if.then
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if.then: ; preds = %for.body
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%0 = sext i32 %i1 to i64
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%arrayidx = getelementptr inbounds i32, i32* %a, i64 %0
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store i32 0, i32* %arrayidx, align 4
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%inc = add nuw nsw i32 %i1, 1
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%cmp = icmp ult i32 %inc, 48
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br i1 %cmp, label %for.body, label %for.end
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for.end: ; preds = %for.cond
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ret void
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}
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