ba9f245b0d
We currently seem to underestimate the size of functions with loops in them, both in terms of absolute code size and in the difficulties of dealing with such code. (Calls, for example, can be tail merged to further reduce codesize). At -Oz, we can then increase code size by inlining small loops multiple times. This attempts to penalise functions with loops at -Oz by adding a CallPenalty for each top level loop in the function. It uses LI (and hence DT) to calculate the number of loops. As we are dealing with minsize, the inline threshold is small and functions at this point should be relatively small, making the construction of these cheap. Differential Revision: https://reviews.llvm.org/D52716 llvm-svn: 346134
50 lines
1.5 KiB
LLVM
50 lines
1.5 KiB
LLVM
; RUN: opt -inline %s -S | FileCheck %s
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target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
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target triple = "thumbv7m-arm-none-eabi"
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; Check we don't inline loops at -Oz. They tend to be larger than we
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; expect.
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; CHECK: define i8* @H
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@digits = constant [16 x i8] c"0123456789ABCDEF", align 1
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define i8* @H(i8* %p, i32 %val, i32 %num) #0 {
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entry:
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br label %do.body
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do.body: ; preds = %do.body, %entry
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%p.addr.0 = phi i8* [ %p, %entry ], [ %incdec.ptr, %do.body ]
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%val.addr.0 = phi i32 [ %val, %entry ], [ %shl, %do.body ]
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%num.addr.0 = phi i32 [ %num, %entry ], [ %dec, %do.body ]
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%shr = lshr i32 %val.addr.0, 28
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%arrayidx = getelementptr inbounds [16 x i8], [16 x i8]* @digits, i32 0, i32 %shr
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%0 = load i8, i8* %arrayidx, align 1
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%incdec.ptr = getelementptr inbounds i8, i8* %p.addr.0, i32 1
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store i8 %0, i8* %p.addr.0, align 1
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%shl = shl i32 %val.addr.0, 4
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%dec = add i32 %num.addr.0, -1
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%tobool = icmp eq i32 %dec, 0
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br i1 %tobool, label %do.end, label %do.body
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do.end: ; preds = %do.body
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%scevgep = getelementptr i8, i8* %p, i32 %num
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ret i8* %scevgep
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}
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define nonnull i8* @call1(i8* %p, i32 %val, i32 %num) #0 {
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entry:
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; CHECK: tail call i8* @H
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%call = tail call i8* @H(i8* %p, i32 %val, i32 %num) #0
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ret i8* %call
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}
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define nonnull i8* @call2(i8* %p, i32 %val) #0 {
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entry:
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; CHECK: tail call i8* @H
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%call = tail call i8* @H(i8* %p, i32 %val, i32 32) #0
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ret i8* %call
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}
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attributes #0 = { minsize optsize }
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