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6a7770b7ae
This changes the SelectionDAG scheduling preference to source order. Soon, the SelectionDAG scheduler can be bypassed saving a nice chunk of compile time. Performance differences that result from this change are often a consequence of register coalescing. The register coalescer is far from perfect. Bugs can be filed for deficiencies. On x86 SandyBridge/Haswell, the source order schedule is often preserved, particularly for small blocks. Register pressure is generally improved over the SD scheduler's ILP mode. However, we are still able to handle large blocks that require latency hiding, unlike the SD scheduler's BURR mode. MI scheduler also attempts to discover the critical path in single-block loops and adjust heuristics accordingly. The MI scheduler relies on the new machine model. This is currently unimplemented for AVX, so we may not be generating the best code yet. Unit tests are updated so they don't depend on SD scheduling heuristics. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192750 91177308-0d34-0410-b5e6-96231b3b80d8
140 lines
5.7 KiB
LLVM
140 lines
5.7 KiB
LLVM
; RUN: llc -mtriple x86_64-apple-macosx -mcpu=corei7-avx -combiner-stress-load-slicing < %s -o - | FileCheck %s --check-prefix=STRESS
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; RUN: llc -mtriple x86_64-apple-macosx -mcpu=corei7-avx < %s -o - | FileCheck %s --check-prefix=REGULAR
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;
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; <rdar://problem/14477220>
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%class.Complex = type { float, float }
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; Check that independant slices leads to independant loads then the slices leads to
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; different register file.
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;
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; The layout is:
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; LSB 0 1 2 3 | 4 5 6 7 MSB
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; Low High
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; The base address points to 0 and is 8-bytes aligned.
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; Low slice starts at 0 (base) and is 8-bytes aligned.
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; High slice starts at 4 (base + 4-bytes) and is 4-bytes aligned.
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;
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; STRESS-LABEL: t1:
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; Load out[out_start + 8].real, this is base + 8 * 8 + 0.
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; STRESS: vmovss 64([[BASE:[^(]+]]), [[OUT_Real:%xmm[0-9]+]]
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; Add low slice: out[out_start].real, this is base + 0.
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; STRESS-NEXT: vaddss ([[BASE]]), [[OUT_Real]], [[RES_Real:%xmm[0-9]+]]
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; Load out[out_start + 8].imm, this is base + 8 * 8 + 4.
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; STRESS-NEXT: vmovss 68([[BASE]]), [[OUT_Imm:%xmm[0-9]+]]
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; Add high slice: out[out_start].imm, this is base + 4.
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; STRESS-NEXT: vaddss 4([[BASE]]), [[OUT_Imm]], [[RES_Imm:%xmm[0-9]+]]
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; Swap Imm and Real.
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; STRESS-NEXT: vinsertps $16, [[RES_Imm]], [[RES_Real]], [[RES_Vec:%xmm[0-9]+]]
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; Put the results back into out[out_start].
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; STRESS-NEXT: vmovq [[RES_Vec]], ([[BASE]])
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;
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; Same for REGULAR, we eliminate register bank copy with each slices.
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; REGULAR-LABEL: t1:
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; Load out[out_start + 8].real, this is base + 8 * 8 + 0.
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; REGULAR: vmovss 64([[BASE:[^)]+]]), [[OUT_Real:%xmm[0-9]+]]
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; Add low slice: out[out_start].real, this is base + 0.
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; REGULAR-NEXT: vaddss ([[BASE]]), [[OUT_Real]], [[RES_Real:%xmm[0-9]+]]
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; Load out[out_start + 8].imm, this is base + 8 * 8 + 4.
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; REGULAR-NEXT: vmovss 68([[BASE]]), [[OUT_Imm:%xmm[0-9]+]]
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; Add high slice: out[out_start].imm, this is base + 4.
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; REGULAR-NEXT: vaddss 4([[BASE]]), [[OUT_Imm]], [[RES_Imm:%xmm[0-9]+]]
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; Swap Imm and Real.
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; REGULAR-NEXT: vinsertps $16, [[RES_Imm]], [[RES_Real]], [[RES_Vec:%xmm[0-9]+]]
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; Put the results back into out[out_start].
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; REGULAR-NEXT: vmovq [[RES_Vec]], ([[BASE]])
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define void @t1(%class.Complex* nocapture %out, i64 %out_start) {
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entry:
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%arrayidx = getelementptr inbounds %class.Complex* %out, i64 %out_start
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%tmp = bitcast %class.Complex* %arrayidx to i64*
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%tmp1 = load i64* %tmp, align 8
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%t0.sroa.0.0.extract.trunc = trunc i64 %tmp1 to i32
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%tmp2 = bitcast i32 %t0.sroa.0.0.extract.trunc to float
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%t0.sroa.2.0.extract.shift = lshr i64 %tmp1, 32
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%t0.sroa.2.0.extract.trunc = trunc i64 %t0.sroa.2.0.extract.shift to i32
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%tmp3 = bitcast i32 %t0.sroa.2.0.extract.trunc to float
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%add = add i64 %out_start, 8
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%arrayidx2 = getelementptr inbounds %class.Complex* %out, i64 %add
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%i.i = getelementptr inbounds %class.Complex* %arrayidx2, i64 0, i32 0
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%tmp4 = load float* %i.i, align 4
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%add.i = fadd float %tmp4, %tmp2
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%retval.sroa.0.0.vec.insert.i = insertelement <2 x float> undef, float %add.i, i32 0
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%r.i = getelementptr inbounds %class.Complex* %arrayidx2, i64 0, i32 1
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%tmp5 = load float* %r.i, align 4
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%add5.i = fadd float %tmp5, %tmp3
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%retval.sroa.0.4.vec.insert.i = insertelement <2 x float> %retval.sroa.0.0.vec.insert.i, float %add5.i, i32 1
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%ref.tmp.sroa.0.0.cast = bitcast %class.Complex* %arrayidx to <2 x float>*
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store <2 x float> %retval.sroa.0.4.vec.insert.i, <2 x float>* %ref.tmp.sroa.0.0.cast, align 4
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ret void
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}
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; Function Attrs: nounwind
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declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #1
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; Function Attrs: nounwind
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declare void @llvm.lifetime.start(i64, i8* nocapture)
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; Function Attrs: nounwind
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declare void @llvm.lifetime.end(i64, i8* nocapture)
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; Check that we do not read outside of the chunk of bits of the original loads.
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;
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; The 64-bits should have been split in one 32-bits and one 16-bits slices.
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; The 16-bits should be zero extended to match the final type.
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;
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; The memory layout is:
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; LSB 0 1 2 3 | 4 5 | 6 7 MSB
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; Low High
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; The base address points to 0 and is 8-bytes aligned.
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; Low slice starts at 0 (base) and is 8-bytes aligned.
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; High slice starts at 6 (base + 6-bytes) and is 2-bytes aligned.
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;
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; STRESS-LABEL: t2:
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; STRESS: movzwl 6([[BASE:[^)]+]]), %eax
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; STRESS-NEXT: addl ([[BASE]]), %eax
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; STRESS-NEXT: ret
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;
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; For the REGULAR heuristic, this is not profitable to slice things that are not
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; next to each other in memory. Here we have a hole with bytes #4-5.
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; REGULAR-LABEL: t2:
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; REGULAR: shrq $48
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define i32 @t2(%class.Complex* nocapture %out, i64 %out_start) {
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%arrayidx = getelementptr inbounds %class.Complex* %out, i64 %out_start
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%bitcast = bitcast %class.Complex* %arrayidx to i64*
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%chunk64 = load i64* %bitcast, align 8
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%slice32_low = trunc i64 %chunk64 to i32
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%shift48 = lshr i64 %chunk64, 48
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%slice32_high = trunc i64 %shift48 to i32
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%res = add i32 %slice32_high, %slice32_low
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ret i32 %res
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}
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; Check that we do not optimize overlapping slices.
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;
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; The 64-bits should NOT have been split in as slices are overlapping.
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; First slice uses bytes numbered 0 to 3.
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; Second slice uses bytes numbered 6 and 7.
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; Third slice uses bytes numbered 4 to 7.
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;
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; STRESS-LABEL: t3:
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; STRESS: shrq $48
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; STRESS: shrq $32
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;
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; REGULAR-LABEL: t3:
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; REGULAR: shrq $48
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; REGULAR: shrq $32
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define i32 @t3(%class.Complex* nocapture %out, i64 %out_start) {
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%arrayidx = getelementptr inbounds %class.Complex* %out, i64 %out_start
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%bitcast = bitcast %class.Complex* %arrayidx to i64*
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%chunk64 = load i64* %bitcast, align 8
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%slice32_low = trunc i64 %chunk64 to i32
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%shift48 = lshr i64 %chunk64, 48
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%slice32_high = trunc i64 %shift48 to i32
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%shift32 = lshr i64 %chunk64, 32
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%slice32_lowhigh = trunc i64 %shift32 to i32
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%tmpres = add i32 %slice32_high, %slice32_low
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%res = add i32 %slice32_lowhigh, %tmpres
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ret i32 %res
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}
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