50b9ca4dda
After https://github.com/llvm/llvm-project/pull/153643, there may be a BranchOnCond with constant condition in the entry block. Simplify those in removeBranchOnConst. This removes a number of redundant conditional branch from entry blocks. In some cases, it may also make the original scalar loop unreachable, because we know it will never execute. In that case, we need to remove the loop from LoopInfo, because all unreachable blocks may dominate each other, making LoopInfo invalid. In those cases, we can also completely remove the loop, for which I'll share a follow-up patch. Depends on https://github.com/llvm/llvm-project/pull/153643. PR: https://github.com/llvm/llvm-project/pull/154510
105 lines
4.1 KiB
LLVM
105 lines
4.1 KiB
LLVM
; RUN: opt -passes=loop-vectorize -force-vector-width=8 -force-vector-interleave=2 -disable-output -debug -S %s 2>&1 | FileCheck --check-prefixes=CHECK %s
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target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
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; REQUIRES: asserts
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; Check if the vector loop condition can be simplified to true for a given
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; VF/IC combination.
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define void @test_tc_less_than_16(ptr %A, i64 %N) {
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; CHECK: LV: Scalarizing: %cmp =
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; CHECK: VPlan 'Initial VPlan for VF={8},UF>=1' {
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; CHECK-NEXT: Live-in vp<[[VF:%.+]]> = VF
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; CHECK-NEXT: Live-in vp<[[VFxUF:%.+]]> = VF * UF
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; CHECK-NEXT: Live-in vp<[[VTC:%.+]]> = vector-trip-count
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; CHECK-NEXT: ir<16> = original trip-count
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; CHECK-EMPTY:
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; CHECK-NEXT: ir-bb<entry>:
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; CHECK-NEXT: Successor(s): scalar.ph, vector.ph
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; CHECK-EMPTY:
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; CHECK-NEXT: vector.ph:
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; CHECK-NEXT: vp<[[END1:%.+]]> = DERIVED-IV ir<16> + vp<[[VTC]]> * ir<-1>
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; CHECK-NEXT: vp<[[END2:%.+]]> = DERIVED-IV ir<%A> + vp<[[VTC]]> * ir<1>
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; CHECK-NEXT: Successor(s): vector loop
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; CHECK-EMPTY:
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; CHECK-NEXT: <x1> vector loop: {
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; CHECK-NEXT: vector.body:
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; CHECK-NEXT: EMIT vp<[[CAN_IV:%.+]]> = CANONICAL-INDUCTION ir<0>, vp<[[CAN_IV_NEXT:%.+]]>
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; CHECK-NEXT: vp<[[STEPS:%.+]]> = SCALAR-STEPS vp<[[CAN_IV]]>, ir<1>, vp<[[VF]]>
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; CHECK-NEXT: EMIT vp<[[PADD:%.+]]> = ptradd ir<%A>, vp<[[STEPS]]>
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; CHECK-NEXT: vp<[[VPTR:%.]]> = vector-pointer vp<[[PADD]]>
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; CHECK-NEXT: WIDEN ir<%l> = load vp<[[VPTR]]>
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; CHECK-NEXT: WIDEN ir<%add> = add nsw ir<%l>, ir<10>
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; CHECK-NEXT: vp<[[VPTR2:%.+]]> = vector-pointer vp<[[PADD]]>
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; CHECK-NEXT: WIDEN store vp<[[VPTR2]]>, ir<%add>
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; CHECK-NEXT: EMIT vp<[[CAN_IV_NEXT]]> = add nuw vp<[[CAN_IV:%.+]]>, vp<[[VFxUF]]>
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; CHECK-NEXT: EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VTC]]>
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; CHECK-NEXT: No successors
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; CHECK-NEXT: }
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; CHECK-NEXT: Successor(s): middle.block
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; CHECK-EMPTY:
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; CHECK-NEXT: middle.block:
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; CHECK-NEXT: EMIT vp<[[C:%.+]]> = icmp eq ir<16>, vp<[[VTC]]>
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; CHECK-NEXT: EMIT branch-on-cond vp<[[C]]>
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; CHECK-NEXT: Successor(s): ir-bb<exit>, scalar.ph
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; CHECK-EMPTY:
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; CHECK-NEXT: ir-bb<exit>:
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; CHECK-NEXT: No successors
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; CHECK-EMPTY:
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; CHECK-NEXT: scalar.ph:
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; CHECK-NEXT: EMIT-SCALAR vp<[[RESUME1:%.+]]> = phi [ vp<[[END1]]>, middle.block ], [ ir<16>, ir-bb<entry> ]
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; CHECK-NEXT: EMIT-SCALAR vp<[[RESUME2:%.+]]>.1 = phi [ vp<[[END2]]>, middle.block ], [ ir<%A>, ir-bb<entry> ]
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; CHECK-NEXT: Successor(s): ir-bb<loop>
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; CHECK-EMPTY:
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; CHECK-NEXT: ir-bb<loop>:
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; CHECK-NEXT: IR %iv = phi i64 [ 16, %entry ], [ %iv.next, %loop ] (extra operand: vp<[[RESUME1]]> from scalar.ph)
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; CHECK-NEXT: IR %p.src = phi ptr [ %A, %entry ], [ %p.src.next, %loop ] (extra operand: vp<[[RESUME2]]>.1 from scalar.ph)
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; CHECK: IR %cmp = icmp eq i64 %iv.next, 0
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; CHECK-NEXT: No successors
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; CHECK-NEXT: }
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;
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; CHECK: Executing best plan with VF=8, UF=2
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; CHECK-NEXT: VPlan 'Final VPlan for VF={8},UF={2}' {
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; CHECK-NEXT: Live-in ir<16> = original trip-count
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; CHECK-EMPTY:
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; CHECK-NEXT: ir-bb<entry>:
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; CHECK-NEXT: Successor(s): vector.ph
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; CHECK-EMPTY:
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; CHECK-NEXT: vector.ph:
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; CHECK-NEXT: Successor(s): vector.body
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; CHECK-EMPTY:
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; CHECK-NEXT: vector.body:
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; CHECK-NEXT: vp<[[VPTR2:%.]]> = vector-pointer ir<%A>, ir<1>
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; CHECK-NEXT: WIDEN ir<%l> = load ir<%A>
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; CHECK-NEXT: WIDEN ir<%l>.1 = load vp<[[VPTR2]]>
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; CHECK-NEXT: WIDEN ir<%add> = add nsw ir<%l>, ir<10>
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; CHECK-NEXT: WIDEN ir<%add>.1 = add nsw ir<%l>.1, ir<10>
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; CHECK-NEXT: WIDEN store ir<%A>, ir<%add>
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; CHECK-NEXT: WIDEN store vp<[[VPTR2]]>, ir<%add>.1
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; CHECK-NEXT: Successor(s): middle.block
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; CHECK-EMPTY:
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; CHECK-NEXT: middle.block:
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; CHECK-NEXT: Successor(s): ir-bb<exit>
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; CHECK-EMPTY:
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; CHECK-NEXT: ir-bb<exit>:
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; CHECK-NEXT: No successors
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; CHECK-NEXT: }
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;
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entry:
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br label %loop
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loop:
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%iv = phi i64 [ 16, %entry ], [ %iv.next, %loop ]
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%p.src = phi ptr [ %A, %entry ], [ %p.src.next, %loop ]
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%p.src.next = getelementptr inbounds i8, ptr %p.src, i64 1
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%l = load i8, ptr %p.src, align 1
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%add = add nsw i8 %l, 10
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store i8 %add, ptr %p.src
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%iv.next = add nsw i64 %iv, -1
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%cmp = icmp eq i64 %iv.next, 0
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br i1 %cmp, label %exit, label %loop
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exit:
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ret void
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}
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