23c2f2e6b2
This patch marks the induction increment of the main induction variable of the vector loop as NUW when not folding the tail. If the tail is not folded, we know that End - Start >= Step (either statically or through the minimum iteration checks). We also know that both Start % Step == 0 and End % Step == 0. We exit the vector loop if %IV + %Step == %End. Hence we must exit the loop before %IV + %Step unsigned overflows and we can mark the induction increment as NUW. This should make SCEV return more precise bounds for the created vector loops, used by later optimizations, like late unrolling. At the moment quite a few tests still need to be updated, but before doing so I'd like to get initial feedback to make sure I am not missing anything. Note that this could probably be further improved by using information from the original IV. Attempt of modeling of the assumption in Alive2: https://alive2.llvm.org/ce/z/H_DL_g Part of a set of fixes required for PR50412. Reviewed By: mkazantsev Differential Revision: https://reviews.llvm.org/D103255
70 lines
3.8 KiB
LLVM
70 lines
3.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -loop-vectorize -force-vector-interleave=3 -force-vector-width=2 -S | FileCheck %s
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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; Make sure the loop is vectorized and unrolled under -Os without folding its
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; tail based on its trip-count being provably divisible by chosen VFxIC.
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define dso_local void @constTC(i32* noalias nocapture %A) optsize {
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; CHECK-LABEL: @constTC(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
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; CHECK: vector.ph:
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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 i32 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i32> poison, i32 [[INDEX]], i32 0
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; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i32> [[BROADCAST_SPLATINSERT]], <2 x i32> poison, <2 x i32> zeroinitializer
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; CHECK-NEXT: [[INDUCTION:%.*]] = add <2 x i32> [[BROADCAST_SPLAT]], <i32 0, i32 1>
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; CHECK-NEXT: [[INDUCTION1:%.*]] = add <2 x i32> [[BROADCAST_SPLAT]], <i32 2, i32 3>
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; CHECK-NEXT: [[INDUCTION2:%.*]] = add <2 x i32> [[BROADCAST_SPLAT]], <i32 4, i32 5>
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; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[INDEX]], 0
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[INDEX]], 2
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; CHECK-NEXT: [[TMP2:%.*]] = add i32 [[INDEX]], 4
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; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, i32* [[A:%.*]], i32 [[TMP0]]
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; CHECK-NEXT: [[TMP4:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP1]]
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; CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[TMP2]]
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; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds i32, i32* [[TMP3]], i32 0
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; CHECK-NEXT: [[TMP7:%.*]] = bitcast i32* [[TMP6]] to <2 x i32>*
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; CHECK-NEXT: store <2 x i32> <i32 13, i32 13>, <2 x i32>* [[TMP7]], align 1
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; CHECK-NEXT: [[TMP8:%.*]] = getelementptr inbounds i32, i32* [[TMP3]], i32 2
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; CHECK-NEXT: [[TMP9:%.*]] = bitcast i32* [[TMP8]] to <2 x i32>*
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; CHECK-NEXT: store <2 x i32> <i32 13, i32 13>, <2 x i32>* [[TMP9]], align 1
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; CHECK-NEXT: [[TMP10:%.*]] = getelementptr inbounds i32, i32* [[TMP3]], i32 4
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; CHECK-NEXT: [[TMP11:%.*]] = bitcast i32* [[TMP10]] to <2 x i32>*
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; CHECK-NEXT: store <2 x i32> <i32 13, i32 13>, <2 x i32>* [[TMP11]], align 1
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i32 [[INDEX]], 6
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; CHECK-NEXT: [[TMP12:%.*]] = icmp eq i32 [[INDEX_NEXT]], 1800
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; CHECK-NEXT: br i1 [[TMP12]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], [[LOOP0:!llvm.loop !.*]]
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; CHECK: middle.block:
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; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i32 1800, 1800
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; CHECK-NEXT: br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
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; CHECK: scalar.ph:
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; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i32 [ 1800, [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
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; CHECK-NEXT: br label [[LOOP:%.*]]
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; CHECK: loop:
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; CHECK-NEXT: [[RIV:%.*]] = phi i32 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[RIVPLUS1:%.*]], [[LOOP]] ]
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds i32, i32* [[A]], i32 [[RIV]]
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; CHECK-NEXT: store i32 13, i32* [[ARRAYIDX]], align 1
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; CHECK-NEXT: [[RIVPLUS1]] = add nuw nsw i32 [[RIV]], 1
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; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[RIVPLUS1]], 1800
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; CHECK-NEXT: br i1 [[COND]], label [[EXIT]], label [[LOOP]], [[LOOP2:!llvm.loop !.*]]
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; CHECK: exit:
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; CHECK-NEXT: ret void
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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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%riv = phi i32 [ 0, %entry ], [ %rivPlus1, %loop ]
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%arrayidx = getelementptr inbounds i32, i32* %A, i32 %riv
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store i32 13, i32* %arrayidx, align 1
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%rivPlus1 = add nuw nsw i32 %riv, 1
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%cond = icmp eq i32 %rivPlus1, 1800
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br i1 %cond, label %exit, label %loop
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exit:
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ret void
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}
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