[AArch64] Precommit some more LD1R splat tests for scalar int/fp loads

[SjoerdMeijer]

Summary

Just a quick check whether you're happy with adding some LD1R tests, and I moved that comment around a bit.
These tests are for scalar integer and FP loads, the existing ones are for vector loads.

The context is of this is https://github.com/llvm/llvm-project/issues/61047, and next I want to actually start looking into these LD1R costs.

[dmgreen]

Additional tests sounds OK. We don't always match splats to a single cost like we should.

I tend to add many tests to one function because the amount of boilerplate code is otherwise quite high, but either way sounds fine (and most other costmodel tests are smaller sets of instructions).

[SjoerdMeijer]

In D145067#4162019, @dmgreen wrote:

Additional tests sounds OK. We don't always match splats to a single cost like we should.

The LD1R is a high latency instruction, the SWOG says a latency of 8.

[SjoerdMeijer]

(accidentally pressed enter)

Was saying that it is a high latency instruction, so somewhere I want to compensate for that. I think this shows interesting differences. The insertelement seems expensive for the integer variant (4) while it is free for the FP cases.

llvm/test/Analysis/CostModel/AArch64/shuffle-load.ll

 ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py
 ; RUN: opt < %s -mtriple=aarch64--linux-gnu -passes="print<cost-model>" 2>&1 -disable-output | FileCheck %s
 
 ; These tests check the costs of ld1r instructions, through the
-; isLegalBroadcastLoad method. The tests use vector loads and splats,
-; as opposed to scalar loads, inserts and splats as that is how
-; getShuffleCost currently recognizes them.
+; isLegalBroadcastLoad method.
 
 target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
 
+; The tests use vector loads and splats, as opposed to scalar loads, inserts
+; and splats as that is how getShuffleCost currently recognizes them.
 define void @shuffle() {
 ; CHECK-LABEL: 'shuffle'
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %lv2i8 = load <2 x i8>, ptr undef, align 2
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sv2i8 = shufflevector <2 x i8> %lv2i8, <2 x i8> undef, <2 x i32> zeroinitializer
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %lv4i8 = load <4 x i8>, ptr undef, align 4
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sv4i8 = shufflevector <4 x i8> %lv4i8, <4 x i8> undef, <4 x i32> zeroinitializer
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lv8i8 = load <8 x i8>, ptr undef, align 8
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sv8i8 = shufflevector <8 x i8> %lv8i8, <8 x i8> undef, <8 x i32> zeroinitializer
;
 
   %lv2f64 = load <2 x double>, ptr undef
   %sv2f64 = shufflevector <2 x double> %lv2f64, <2 x double> undef, <2 x i32> zeroinitializer
   %lv4f64 = load <4 x double>, ptr undef
   %sv4f64 = shufflevector <4 x double> %lv4f64, <4 x double> undef, <4 x i32> zeroinitializer
 
   ret void
 }
+
+; Check ld1r generated from scalar FP loads
+
+define <4 x half> @ld1r_4h_float_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_4h_float_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load half, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %tmp1 = insertelement <4 x half> undef, half %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <4 x half> %tmp1, <4 x half> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x half> %lane
+;
+entry:
+  %tmp = load half, ptr %x, align 2
+  %tmp1 = insertelement <4 x half> undef, half %tmp, i32 0
+  %lane = shufflevector <4 x half> %tmp1, <4 x half> undef, <4 x i32> zeroinitializer
+  ret <4 x half> %lane
+}
+
+define <8 x half> @ld1r_8h_float_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_8h_float_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load half, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %tmp1 = insertelement <8 x half> undef, half %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 21 for instruction: %lane = shufflevector <8 x half> %tmp1, <8 x half> undef, <8 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <8 x half> %lane
+;
+entry:
+  %tmp = load half, ptr %x, align 2
+  %tmp1 = insertelement <8 x half> undef, half %tmp, i32 0
+  %lane = shufflevector <8 x half> %tmp1, <8 x half> undef, <8 x i32> zeroinitializer
+  ret <8 x half> %lane
+}
+
+define <2 x float> @ld1r_2s_float_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_2s_float_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load float, ptr %x, align 4
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %tmp1 = insertelement <2 x float> undef, float %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <2 x float> %tmp1, <2 x float> undef, <2 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x float> %lane
+;
+entry:
+  %tmp = load float, ptr %x, align 4
+  %tmp1 = insertelement <2 x float> undef, float %tmp, i32 0
+  %lane = shufflevector <2 x float> %tmp1, <2 x float> undef, <2 x i32> zeroinitializer
+  ret <2 x float> %lane
+}
+
+define <4 x float> @ld1r_4s_float_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_4s_float_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load float, ptr %x, align 4
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %tmp1 = insertelement <4 x float> undef, float %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <4 x float> %tmp1, <4 x float> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x float> %lane
+;
+entry:
+  %tmp = load float, ptr %x, align 4
+  %tmp1 = insertelement <4 x float> undef, float %tmp, i32 0
+  %lane = shufflevector <4 x float> %tmp1, <4 x float> undef, <4 x i32> zeroinitializer
+  ret <4 x float> %lane
+}
+
+define <2 x double> @ld1r_2d_double_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_2d_double_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load double, ptr %x, align 4
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %tmp1 = insertelement <2 x double> undef, double %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <2 x double> %tmp1, <2 x double> undef, <2 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x double> %lane
+;
+entry:
+  %tmp = load double, ptr %x, align 4
+  %tmp1 = insertelement <2 x double> undef, double %tmp, i32 0
+  %lane = shufflevector <2 x double> %tmp1, <2 x double> undef, <2 x i32> zeroinitializer
+  ret <2 x double> %lane
+}
+
+; Check ld1r generated from scalar integer loads
+
+define <8 x i8> @ld1r_8b_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_8b_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i8, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <8 x i8> undef, i8 %tmp, i8 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <8 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <8 x i8> %lane
+;
+entry:
+  %tmp = load i8, ptr %x, align 2
+  %tmp1 = insertelement <8 x i8> undef, i8 %tmp, i8 0
+  %lane = shufflevector <8 x i8> %tmp1, <8 x i8> undef, <8 x i32> zeroinitializer
+  ret <8 x i8> %lane
+}
+
+define <16 x i8> @ld1r_16b_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_16b_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i8, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <16 x i8> undef, i8 %tmp, i8 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <16 x i8> %tmp1, <16 x i8> undef, <16 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <16 x i8> %lane
+;
+entry:
+  %tmp = load i8, ptr %x, align 2
+  %tmp1 = insertelement <16 x i8> undef, i8 %tmp, i8 0
+  %lane = shufflevector <16 x i8> %tmp1, <16 x i8> undef, <16 x i32> zeroinitializer
+  ret <16 x i8> %lane
+}
+
+define <4 x i16> @ld1r_4h_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_4h_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i16, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <4 x i16> undef, i16 %tmp, i16 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <4 x i16> %tmp1, <4 x i16> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x i16> %lane
+;
+entry:
+  %tmp = load i16, ptr %x, align 2
+  %tmp1 = insertelement <4 x i16> undef, i16 %tmp, i16 0
+  %lane = shufflevector <4 x i16> %tmp1, <4 x i16> undef, <4 x i32> zeroinitializer
+  ret <4 x i16> %lane
+}
+
+define <8 x i16> @ld1r_8h_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_8h_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i16, ptr %x, align 2
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <8 x i16> undef, i16 %tmp, i16 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <8 x i16> %tmp1, <8 x i16> undef, <8 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <8 x i16> %lane
+;
+entry:
+  %tmp = load i16, ptr %x, align 2
+  %tmp1 = insertelement <8 x i16> undef, i16 %tmp, i16 0
+  %lane = shufflevector <8 x i16> %tmp1, <8 x i16> undef, <8 x i32> zeroinitializer
+  ret <8 x i16> %lane
+}
+
+define <2 x i32> @ld1r_2s_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_2s_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i32, ptr %x, align 4
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <2 x i32> undef, i32 %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <2 x i32> %tmp1, <2 x i32> undef, <2 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i32> %lane
+;
+entry:
+  %tmp = load i32, ptr %x, align 4
+  %tmp1 = insertelement <2 x i32> undef, i32 %tmp, i32 0
+  %lane = shufflevector <2 x i32> %tmp1, <2 x i32> undef, <2 x i32> zeroinitializer
+  ret <2 x i32> %lane
+}
+
+define <4 x i32> @ld1r_4s_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_4s_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i32, ptr %x, align 4
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <4 x i32> undef, i32 %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <4 x i32> %tmp1, <4 x i32> undef, <4 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x i32> %lane
+;
+entry:
+  %tmp = load i32, ptr %x, align 4
+  %tmp1 = insertelement <4 x i32> undef, i32 %tmp, i32 0
+  %lane = shufflevector <4 x i32> %tmp1, <4 x i32> undef, <4 x i32> zeroinitializer
+  ret <4 x i32> %lane
+}
+
+define <2 x i64> @ld1r_2d_int_shuff(ptr nocapture %x) {
+; CHECK-LABEL: 'ld1r_2d_int_shuff'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %tmp = load i64, ptr %x, align 8
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %tmp1 = insertelement <2 x i64> undef, i64 %tmp, i32 0
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %lane = shufflevector <2 x i64> %tmp1, <2 x i64> undef, <2 x i32> zeroinitializer
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <2 x i64> %lane
+;
+entry:
+  %tmp = load i64, ptr %x, align 8
+  %tmp1 = insertelement <2 x i64> undef, i64 %tmp, i32 0
+  %lane = shufflevector <2 x i64> %tmp1, <2 x i64> undef, <2 x i32> zeroinitializer
+  ret <2 x i64> %lane
+}