44edc6fd2c
Summary: Replacing uses of IV outside of the loop is likely generally useful, but `rewriteLoopExitValues()` is cautious, and if it isn't told to always perform the replacement, and there are hard uses of IV in loop, it doesn't replace. In [[ https://bugs.llvm.org/show_bug.cgi?id=44668 | PR44668 ]], that prevents `-indvars` from replacing uses of induction variable after the loop, which might be one of the optimization failures preventing that code from being vectorized. Instead, now that the cost model is fixed, i believe we should be a little bit more optimistic, and also perform replacement if we believe it is within our budget. Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=44668 | PR44668 ]]. Reviewers: reames, mkazantsev, asbirlea, fhahn, skatkov Reviewed By: mkazantsev Subscribers: nikic, hiraditya, zzheng, javed.absar, dmgreen, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D73501
66 lines
2.7 KiB
LLVM
66 lines
2.7 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; PR28705
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; RUN: opt < %s -indvars -S | FileCheck %s
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; Check IndVarSimplify doesn't replace external use of the induction var
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; "%inc.i.i" with "%.sroa.speculated + 1" because it is not profitable.
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;
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;
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define void @foo(i32 %sub.ptr.div.i, i8* %ref.i1174) local_unnamed_addr {
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; CHECK-LABEL: @foo(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP_I1137:%.*]] = icmp ugt i32 [[SUB_PTR_DIV_I:%.*]], 3
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; CHECK-NEXT: [[DOTSROA_SPECULATED:%.*]] = select i1 [[CMP_I1137]], i32 3, i32 [[SUB_PTR_DIV_I]]
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; CHECK-NEXT: [[CMP6483126:%.*]] = icmp eq i32 [[DOTSROA_SPECULATED]], 0
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; CHECK-NEXT: br i1 [[CMP6483126]], label [[XZ_EXIT:%.*]], label [[FOR_BODY650_LR_PH:%.*]]
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; CHECK: for.body650.lr.ph:
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; CHECK-NEXT: br label [[FOR_BODY650:%.*]]
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; CHECK: loopexit:
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; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[DOTSROA_SPECULATED]], 1
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; CHECK-NEXT: br label [[XZ_EXIT]]
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; CHECK: XZ.exit:
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; CHECK-NEXT: [[DB_SROA_9_0_LCSSA:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[TMP0]], [[LOOPEXIT:%.*]] ]
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; CHECK-NEXT: br label [[END:%.*]]
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; CHECK: for.body650:
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; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[FOR_BODY650_LR_PH]] ], [ [[INC655:%.*]], [[FOR_BODY650]] ]
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; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ 1, [[FOR_BODY650_LR_PH]] ], [ [[INC_I_I:%.*]], [[FOR_BODY650]] ]
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; CHECK-NEXT: [[ARRAYIDX_I_I1105:%.*]] = getelementptr inbounds i8, i8* [[REF_I1174:%.*]], i32 [[IV2]]
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; CHECK-NEXT: store i8 7, i8* [[ARRAYIDX_I_I1105]], align 1
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; CHECK-NEXT: [[INC_I_I]] = add nuw nsw i32 [[IV2]], 1
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; CHECK-NEXT: [[INC655]] = add nuw nsw i32 [[IV]], 1
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; CHECK-NEXT: [[CMP648:%.*]] = icmp eq i32 [[INC655]], [[DOTSROA_SPECULATED]]
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; CHECK-NEXT: br i1 [[CMP648]], label [[LOOPEXIT]], label [[FOR_BODY650]]
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; CHECK: end:
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; CHECK-NEXT: ret void
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;
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entry:
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%cmp.i1137 = icmp ugt i32 %sub.ptr.div.i, 3
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%.sroa.speculated = select i1 %cmp.i1137, i32 3, i32 %sub.ptr.div.i
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%cmp6483126 = icmp eq i32 %.sroa.speculated, 0
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br i1 %cmp6483126, label %XZ.exit, label %for.body650.lr.ph
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for.body650.lr.ph:
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br label %for.body650
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loopexit:
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%inc.i.i.lcssa = phi i32 [ %inc.i.i, %for.body650 ]
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br label %XZ.exit
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XZ.exit:
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%DB.sroa.9.0.lcssa = phi i32 [ 1, %entry ], [ %inc.i.i.lcssa, %loopexit ]
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br label %end
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for.body650:
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%iv = phi i32 [ 0, %for.body650.lr.ph ], [ %inc655, %for.body650 ]
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%iv2 = phi i32 [ 1, %for.body650.lr.ph ], [ %inc.i.i, %for.body650 ]
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%arrayidx.i.i1105 = getelementptr inbounds i8, i8* %ref.i1174, i32 %iv2
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store i8 7, i8* %arrayidx.i.i1105, align 1
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%inc.i.i = add i32 %iv2, 1
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%inc655 = add i32 %iv, 1
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%cmp648 = icmp eq i32 %inc655, %.sroa.speculated
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br i1 %cmp648, label %loopexit, label %for.body650
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end:
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ret void
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}
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