Florian Hahn 86813aa786
[VPlan] Add dedicated user for resume phi with epilogue vectorization.
Epilogue vectorization currently relies on the resume phi for the
canonical induction being always available, which is why VPPhi are
considered to have side-effects, to prevent their removal.

This patch adds a new ResumeForEpilogue opcode to mark the resume phi as
used for epilogue vectorization. This allows treating VPPhis in general
as not having side-effects, enabling removal of unused VPPhis.
2025-08-10 21:21:16 +01:00

106 lines
5.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -p loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -prefer-predicate-over-epilogue=predicate-dont-vectorize -S %s | FileCheck %s
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128-Fn32"
define void @tail_fold_switch(ptr %dst, i32 %0) {
; CHECK-LABEL: define void @tail_fold_switch(
; CHECK-SAME: ptr [[DST:%.*]], i32 [[TMP0:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
; CHECK: [[VECTOR_PH]]:
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[TMP0]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: [[TMP2:%.*]] = icmp eq <4 x i32> [[BROADCAST_SPLAT]], splat (i32 1)
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE6:.*]] ]
; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i8> [ <i8 0, i8 1, i8 2, i8 3>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE6]] ]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ule <4 x i8> [[VEC_IND]], splat (i8 4)
; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[TMP1]], <4 x i1> [[TMP2]], <4 x i1> zeroinitializer
; CHECK-NEXT: [[TMP4:%.*]] = extractelement <4 x i1> [[TMP3]], i32 0
; CHECK-NEXT: br i1 [[TMP4]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
; CHECK: [[PRED_STORE_IF]]:
; CHECK-NEXT: [[TMP5:%.*]] = add i64 [[INDEX]], 0
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, ptr [[DST]], i64 [[TMP5]]
; CHECK-NEXT: store i32 0, ptr [[TMP6]], align 4
; CHECK-NEXT: br label %[[PRED_STORE_CONTINUE]]
; CHECK: [[PRED_STORE_CONTINUE]]:
; CHECK-NEXT: [[TMP7:%.*]] = extractelement <4 x i1> [[TMP3]], i32 1
; CHECK-NEXT: br i1 [[TMP7]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2:.*]]
; CHECK: [[PRED_STORE_IF1]]:
; CHECK-NEXT: [[TMP8:%.*]] = add i64 [[INDEX]], 1
; CHECK-NEXT: [[TMP9:%.*]] = getelementptr inbounds i32, ptr [[DST]], i64 [[TMP8]]
; CHECK-NEXT: store i32 0, ptr [[TMP9]], align 4
; CHECK-NEXT: br label %[[PRED_STORE_CONTINUE2]]
; CHECK: [[PRED_STORE_CONTINUE2]]:
; CHECK-NEXT: [[TMP10:%.*]] = extractelement <4 x i1> [[TMP3]], i32 2
; CHECK-NEXT: br i1 [[TMP10]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4:.*]]
; CHECK: [[PRED_STORE_IF3]]:
; CHECK-NEXT: [[TMP11:%.*]] = add i64 [[INDEX]], 2
; CHECK-NEXT: [[TMP12:%.*]] = getelementptr inbounds i32, ptr [[DST]], i64 [[TMP11]]
; CHECK-NEXT: store i32 0, ptr [[TMP12]], align 4
; CHECK-NEXT: br label %[[PRED_STORE_CONTINUE4]]
; CHECK: [[PRED_STORE_CONTINUE4]]:
; CHECK-NEXT: [[TMP13:%.*]] = extractelement <4 x i1> [[TMP3]], i32 3
; CHECK-NEXT: br i1 [[TMP13]], label %[[PRED_STORE_IF5:.*]], label %[[PRED_STORE_CONTINUE6]]
; CHECK: [[PRED_STORE_IF5]]:
; CHECK-NEXT: [[TMP14:%.*]] = add i64 [[INDEX]], 3
; CHECK-NEXT: [[TMP15:%.*]] = getelementptr inbounds i32, ptr [[DST]], i64 [[TMP14]]
; CHECK-NEXT: store i32 0, ptr [[TMP15]], align 4
; CHECK-NEXT: br label %[[PRED_STORE_CONTINUE6]]
; CHECK: [[PRED_STORE_CONTINUE6]]:
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i8> [[VEC_IND]], splat (i8 4)
; CHECK-NEXT: [[TMP16:%.*]] = icmp eq i64 [[INDEX_NEXT]], 8
; CHECK-NEXT: br i1 [[TMP16]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
; CHECK: [[MIDDLE_BLOCK]]:
; CHECK-NEXT: br label %[[EXIT:.*]]
; CHECK: [[SCALAR_PH]]:
; CHECK-NEXT: br label %[[LOOP_HEADER:.*]]
; CHECK: [[LOOP_HEADER]]:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
; CHECK-NEXT: switch i32 [[TMP0]], label %[[LOOP_LATCH]] [
; CHECK-NEXT: i32 0, label %[[LOOP_LATCH]]
; CHECK-NEXT: i32 1, label %[[IF_THEN:.*]]
; CHECK-NEXT: ]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i32, ptr [[DST]], i64 [[IV]]
; CHECK-NEXT: store i32 0, ptr [[GEP]], align 4
; CHECK-NEXT: br label %[[LOOP_LATCH]]
; CHECK: [[LOOP_LATCH]]:
; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
; CHECK-NEXT: [[EC:%.*]] = icmp eq i64 [[IV]], 4
; CHECK-NEXT: br i1 [[EC]], label %[[EXIT]], label %[[LOOP_HEADER]], !llvm.loop [[LOOP3:![0-9]+]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: ret void
;
entry:
br label %loop.header
loop.header:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
switch i32 %0, label %loop.latch [
i32 0, label %loop.latch
i32 1, label %if.then
]
if.then:
%gep = getelementptr inbounds i32, ptr %dst, i64 %iv
store i32 0, ptr %gep, align 4
br label %loop.latch
loop.latch:
%iv.next = add i64 %iv, 1
%ec = icmp eq i64 %iv, 4
br i1 %ec, label %exit, label %loop.header
exit:
ret void
}
;.
; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
;.