90ba33099c
This patch canonicalizes getelementptr instructions with constant indices to use the `i8` source element type. This makes it easier for optimizations to recognize that two GEPs are identical, because they don't need to see past many different ways to express the same offset. This is a first step towards https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699. This is limited to constant GEPs only for now, as they have a clear canonical form, while we're not yet sure how exactly to deal with variable indices. The test llvm/test/Transforms/PhaseOrdering/switch_with_geps.ll gives two representative examples of the kind of optimization improvement we expect from this change. In the first test SimplifyCFG can now realize that all switch branches are actually the same. In the second test it can convert it into simple arithmetic. These are representative of common optimization failures we see in Rust. Fixes https://github.com/llvm/llvm-project/issues/69841.
123 lines
6.8 KiB
LLVM
123 lines
6.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; This is the loop in c++ being vectorize in this file with
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; shuffle reverse
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;#pragma clang loop vectorize_width(4, fixed)
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; for (long int i = N - 1; i >= 0; i--)
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; {
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; if (cond[i])
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; a[i] += 1;
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; }
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; The test checks if the mask is being correctly created, reverted and used
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; RUN: opt -passes=loop-vectorize,dce,instcombine -mtriple aarch64-linux-gnu -S \
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; RUN: -prefer-predicate-over-epilogue=scalar-epilogue < %s | FileCheck %s
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target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
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target triple = "aarch64-unknown-linux-gnu"
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define void @vector_reverse_mask_v4i1(ptr noalias %a, ptr noalias %cond, i64 %N) #0 {
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; CHECK-LABEL: @vector_reverse_mask_v4i1(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP7:%.*]] = icmp sgt i64 [[N:%.*]], 0
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; CHECK-NEXT: br i1 [[CMP7]], label [[FOR_BODY_PREHEADER:%.*]], label [[FOR_COND_CLEANUP:%.*]]
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; CHECK: for.body.preheader:
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; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 8
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; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
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; CHECK: vector.ph:
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; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[N]], 9223372036854775800
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; CHECK-NEXT: [[IND_END:%.*]] = and i64 [[N]], 7
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; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
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; CHECK: vector.body:
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; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[TMP0:%.*]] = xor i64 [[INDEX]], -1
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; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[TMP0]], [[N]]
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; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds double, ptr [[COND:%.*]], i64 [[TMP1]]
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; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i64 -24
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; CHECK-NEXT: [[TMP4:%.*]] = getelementptr inbounds i8, ptr [[TMP2]], i64 -56
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; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x double>, ptr [[TMP3]], align 8
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; CHECK-NEXT: [[REVERSE:%.*]] = shufflevector <4 x double> [[WIDE_LOAD]], <4 x double> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
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; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = load <4 x double>, ptr [[TMP4]], align 8
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; CHECK-NEXT: [[REVERSE2:%.*]] = shufflevector <4 x double> [[WIDE_LOAD1]], <4 x double> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
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; CHECK-NEXT: [[TMP5:%.*]] = fcmp une <4 x double> [[REVERSE]], zeroinitializer
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; CHECK-NEXT: [[TMP6:%.*]] = fcmp une <4 x double> [[REVERSE2]], zeroinitializer
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; CHECK-NEXT: [[TMP7:%.*]] = getelementptr double, ptr [[A:%.*]], i64 [[TMP1]]
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; CHECK-NEXT: [[TMP8:%.*]] = getelementptr i8, ptr [[TMP7]], i64 -24
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; CHECK-NEXT: [[TMP9:%.*]] = getelementptr i8, ptr [[TMP7]], i64 -56
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; CHECK-NEXT: [[REVERSE3:%.*]] = shufflevector <4 x i1> [[TMP5]], <4 x i1> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
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; CHECK-NEXT: [[REVERSE4:%.*]] = shufflevector <4 x i1> [[TMP6]], <4 x i1> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
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; CHECK-NEXT: [[WIDE_MASKED_LOAD:%.*]] = call <4 x double> @llvm.masked.load.v4f64.p0(ptr [[TMP8]], i32 8, <4 x i1> [[REVERSE3]], <4 x double> poison)
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; CHECK-NEXT: [[WIDE_MASKED_LOAD6:%.*]] = call <4 x double> @llvm.masked.load.v4f64.p0(ptr [[TMP9]], i32 8, <4 x i1> [[REVERSE4]], <4 x double> poison)
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; CHECK-NEXT: [[TMP10:%.*]] = fadd <4 x double> [[WIDE_MASKED_LOAD]], <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
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; CHECK-NEXT: [[TMP11:%.*]] = fadd <4 x double> [[WIDE_MASKED_LOAD6]], <double 1.000000e+00, double 1.000000e+00, double 1.000000e+00, double 1.000000e+00>
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; CHECK-NEXT: call void @llvm.masked.store.v4f64.p0(<4 x double> [[TMP10]], ptr [[TMP8]], i32 8, <4 x i1> [[REVERSE3]])
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; CHECK-NEXT: call void @llvm.masked.store.v4f64.p0(<4 x double> [[TMP11]], ptr [[TMP9]], i32 8, <4 x i1> [[REVERSE4]])
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 8
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; CHECK-NEXT: [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
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; CHECK-NEXT: br i1 [[TMP12]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
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; CHECK: middle.block:
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; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N_VEC]], [[N]]
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; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_COND_CLEANUP_LOOPEXIT:%.*]], label [[SCALAR_PH]]
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; CHECK: scalar.ph:
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; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], [[MIDDLE_BLOCK]] ], [ [[N]], [[FOR_BODY_PREHEADER]] ]
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; CHECK-NEXT: br label [[FOR_BODY:%.*]]
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; CHECK: for.cond.cleanup.loopexit:
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; CHECK-NEXT: br label [[FOR_COND_CLEANUP]]
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; CHECK: for.cond.cleanup:
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; CHECK-NEXT: ret void
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; CHECK: for.body:
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; CHECK-NEXT: [[I_08_IN:%.*]] = phi i64 [ [[I_08:%.*]], [[FOR_INC:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
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; CHECK-NEXT: [[I_08]] = add nsw i64 [[I_08_IN]], -1
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds double, ptr [[COND]], i64 [[I_08]]
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; CHECK-NEXT: [[TMP13:%.*]] = load double, ptr [[ARRAYIDX]], align 8
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; CHECK-NEXT: [[TOBOOL:%.*]] = fcmp une double [[TMP13]], 0.000000e+00
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; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_THEN:%.*]], label [[FOR_INC]]
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; CHECK: if.then:
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; CHECK-NEXT: [[ARRAYIDX1:%.*]] = getelementptr inbounds double, ptr [[A]], i64 [[I_08]]
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; CHECK-NEXT: [[TMP14:%.*]] = load double, ptr [[ARRAYIDX1]], align 8
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; CHECK-NEXT: [[ADD:%.*]] = fadd double [[TMP14]], 1.000000e+00
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; CHECK-NEXT: store double [[ADD]], ptr [[ARRAYIDX1]], align 8
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; CHECK-NEXT: br label [[FOR_INC]]
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; CHECK: for.inc:
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; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i64 [[I_08_IN]], 1
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; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP_LOOPEXIT]], !llvm.loop [[LOOP4:![0-9]+]]
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;
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entry:
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%cmp7 = icmp sgt i64 %N, 0
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br i1 %cmp7, label %for.body, label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond.cleanup, %entry
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ret void
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for.body: ; preds = %for.body, %entry
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%i.08.in = phi i64 [ %i.08, %for.inc ], [ %N, %entry ]
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%i.08 = add nsw i64 %i.08.in, -1
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%arrayidx = getelementptr inbounds double, ptr %cond, i64 %i.08
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%0 = load double, ptr %arrayidx, align 8
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%tobool = fcmp une double %0, 0.000000e+00
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br i1 %tobool, label %if.then, label %for.inc
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if.then: ; preds = %for.body
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%arrayidx1 = getelementptr inbounds double, ptr %a, i64 %i.08
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%1 = load double, ptr %arrayidx1, align 8
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%add = fadd double %1, 1.000000e+00
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store double %add, ptr %arrayidx1, align 8
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br label %for.inc
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for.inc: ; preds = %for.body, %if.then
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%cmp = icmp sgt i64 %i.08.in, 1
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br i1 %cmp, label %for.body, label %for.cond.cleanup, !llvm.loop !0
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}
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attributes #0 = {"target-cpu"="generic" "target-features"="+neon,+sve" vscale_range(2,0) }
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!0 = distinct !{!0, !1, !2, !3, !4, !5}
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!1 = !{!"llvm.loop.mustprogress"}
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!2 = !{!"llvm.loop.vectorize.width", i32 4}
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!3 = !{!"llvm.loop.vectorize.scalable.enable", i1 false}
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!4 = !{!"llvm.loop.vectorize.enable", i1 true}
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!5 = !{!"llvm.loop.interleave.count", i32 2}
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