[PATCH] D153004: [LSR] Consider post-inc form when creating extends/truncates.

[Peixin Qiao via Phabricator via llvm-commits]

peixin added a comment.

There may be one more case which this patch does not capture? Check the following input:

  target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
  target triple = "aarch64-unknown-linux-gnu"
  
  @c = internal global i32 0, align 4
  @g = dso_local local_unnamed_addr global ptr @c, align 8
  @h = dso_local global i8 0, align 4
  @j = dso_local local_unnamed_addr global ptr @h, align 8
  @b = internal unnamed_addr global i32 0, align 4
  @e = dso_local local_unnamed_addr global i16 0, align 4
  @f = dso_local local_unnamed_addr global i64 0, align 8
  @l = dso_local local_unnamed_addr global i64 0, align 8
  @i = dso_local local_unnamed_addr global i64 0, align 8
  @.str = private unnamed_addr constant [5 x i8] c"%lX\0A\00", align 1
  @a = dso_local local_unnamed_addr global i8 0, align 1
  
  ; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn uwtable
  define dso_local void @n(ptr nocapture noundef %0) {
    ret void
  }
  
  ; Function Attrs: nofree nounwind uwtable
  define dso_local i32 @main() {
    %1 = load ptr, ptr @g, align 8
    %2 = load i64, ptr @f, align 8
    br label %3
  
  3:                                                ; preds = %0, %18
    %4 = phi i32 [ 0, %0 ], [ %19, %18 ]
    %5 = phi i64 [ %2, %0 ], [ %15, %18 ]
    br label %6
  
  6:                                                ; preds = %3, %6
    %7 = phi i32 [ 1, %3 ], [ %10, %6 ]
    %8 = phi i64 [ %5, %3 ], [ %9, %6 ]
    %9 = add nsw i64 %8, 1
    %10 = add nsw i32 %7, -1
    %11 = icmp sgt i32 %7, 0
    br i1 %11, label %6, label %12
  
  12:                                               ; preds = %6, %12
    %13 = phi i32 [ %16, %12 ], [ 1, %6 ]
    %14 = phi i64 [ %15, %12 ], [ %9, %6 ]
    %15 = add nsw i64 %14, 1
    %16 = add nsw i32 %13, -1
    %17 = icmp sgt i32 %13, 0
    br i1 %17, label %12, label %18
  
  18:                                               ; preds = %12
    %19 = add nuw nsw i32 %4, 1
    %20 = icmp eq i32 %19, 8
    br i1 %20, label %21, label %3
  
  21:                                               ; preds = %18
    store i32 %16, ptr @b, align 4
    store i32 0, ptr %1, align 4
    %22 = zext i32 %13 to i64
    store i16 -1, ptr @e, align 4
    store i64 %15, ptr @f, align 8
    store i64 %14, ptr @l, align 8
    store i64 %22, ptr @i, align 8
    %23 = urem i32 %16, 53
    %24 = trunc i32 %23 to i8
    %25 = load ptr, ptr @j, align 8
    store i8 %24, ptr %25, align 1
    %26 = load i8, ptr @h, align 4
    %27 = xor i8 %26, 5
    %28 = zext i8 %27 to i64
    %29 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull @.str, i64 noundef %28)
    ret i32 0
  }
  
  declare noundef i32 @printf(ptr nocapture noundef readonly, ...)

  $ opt -loop-reduce reduced.ll -S -o out.ll && clang out.ll -o a.out && ./a.out
  B
  $ clang reduced.ll -o a.out && ./a.out
  2C


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D153004/new/

https://reviews.llvm.org/D153004