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.
111 lines
5.5 KiB
LLVM
111 lines
5.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=loop-vectorize,instcombine -force-vector-width=4 -force-vector-interleave=1 -S | FileCheck %s
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target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
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;
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define void @vector_gep_stored(ptr %a, ptr %b, i64 %n) {
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; CHECK-LABEL: @vector_gep_stored(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
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; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 4
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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 [[SMAX]], 9223372036854775804
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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: [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds i32, ptr [[B:%.*]], <4 x i64> [[VEC_IND]]
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; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds ptr, ptr [[A:%.*]], i64 [[INDEX]]
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; CHECK-NEXT: store <4 x ptr> [[TMP0]], ptr [[TMP1]], align 8
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
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; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], <i64 4, i64 4, i64 4, i64 4>
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; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
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; CHECK-NEXT: br i1 [[TMP2]], 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 [[SMAX]], [[N_VEC]]
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; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
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; CHECK: scalar.ph:
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; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
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; CHECK-NEXT: br label [[FOR_BODY:%.*]]
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; CHECK: for.body:
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; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[FOR_BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
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; CHECK-NEXT: [[VAR0:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[I]]
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; CHECK-NEXT: [[VAR1:%.*]] = getelementptr inbounds ptr, ptr [[A]], i64 [[I]]
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; CHECK-NEXT: store ptr [[VAR0]], ptr [[VAR1]], align 8
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; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
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; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
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; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END]], !llvm.loop [[LOOP3:![0-9]+]]
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; CHECK: for.end:
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; CHECK-NEXT: ret void
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;
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entry:
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br label %for.body
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for.body:
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%i = phi i64 [ %i.next, %for.body ], [ 0, %entry ]
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%var0 = getelementptr inbounds i32, ptr %b, i64 %i
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%var1 = getelementptr inbounds ptr, ptr %a, i64 %i
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store ptr %var0, ptr %var1, align 8
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%i.next = add nuw nsw i64 %i, 1
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%cond = icmp slt i64 %i.next, %n
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br i1 %cond, label %for.body, label %for.end
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for.end:
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ret void
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}
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;
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define void @uniform_vector_gep_stored(ptr %a, ptr %b, i64 %n) {
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; CHECK-LABEL: @uniform_vector_gep_stored(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
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; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 4
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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 [[SMAX]], 9223372036854775804
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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:%.*]] = getelementptr inbounds i8, ptr [[B:%.*]], i64 4
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; CHECK-NEXT: [[DOTSPLATINSERT:%.*]] = insertelement <4 x ptr> poison, ptr [[TMP0]], i64 0
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; CHECK-NEXT: [[DOTSPLAT:%.*]] = shufflevector <4 x ptr> [[DOTSPLATINSERT]], <4 x ptr> poison, <4 x i32> zeroinitializer
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; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds ptr, ptr [[A:%.*]], i64 [[INDEX]]
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; CHECK-NEXT: store <4 x ptr> [[DOTSPLAT]], ptr [[TMP1]], align 8
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
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; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
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; CHECK-NEXT: br i1 [[TMP2]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
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; CHECK: middle.block:
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; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[SMAX]], [[N_VEC]]
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; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
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; CHECK: scalar.ph:
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; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
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; CHECK-NEXT: br label [[FOR_BODY:%.*]]
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; CHECK: for.body:
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; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[FOR_BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
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; CHECK-NEXT: [[VAR0:%.*]] = getelementptr inbounds i8, ptr [[B]], i64 4
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; CHECK-NEXT: [[VAR1:%.*]] = getelementptr inbounds ptr, ptr [[A]], i64 [[I]]
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; CHECK-NEXT: store ptr [[VAR0]], ptr [[VAR1]], align 8
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; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
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; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
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; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END]], !llvm.loop [[LOOP5:![0-9]+]]
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; CHECK: for.end:
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; CHECK-NEXT: ret void
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;
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entry:
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br label %for.body
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for.body:
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%i = phi i64 [ %i.next, %for.body ], [ 0, %entry ]
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%var0 = getelementptr inbounds i32, ptr %b, i64 1
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%var1 = getelementptr inbounds ptr, ptr %a, i64 %i
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store ptr %var0, ptr %var1, align 8
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%i.next = add nuw nsw i64 %i, 1
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%cond = icmp slt i64 %i.next, %n
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br i1 %cond, label %for.body, label %for.end
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for.end:
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ret void
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}
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