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Bug 5 - [inline] Opt freezes when used with -inline pass
Summary: [inline] Opt freezes when used with -inline pass
Status: RESOLVED FIXED
Alias: None
Product: tools
Classification: Unclassified
Component: opt (show other bugs)
Version: trunk
Hardware: PC Linux
: P normal
Assignee: Chris Lattner
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2003-10-07 14:03 PDT by John T. Criswell
Modified: 2010-02-22 12:43 PST (History)
1 user (show)

See Also:
Fixed By Commit(s):


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Description John T. Criswell 2003-10-07 14:03:15 PDT
The opt program appears to freeze when it uses the -inline option on bytecode
assembled from the assembly code below.  In reality, it is either an infinite
loop or just a gigantic running time:

implementation

declare int "atoi"(sbyte *)

ulong "fib"(ulong %n)
begin
  setlt ulong %n, 2       ; {bool}:0
  br bool %0, label %BaseCase, label %RecurseCase

BaseCase:
  ret ulong 1

RecurseCase:
  %n2 = sub ulong %n, 2
  %n1 = sub ulong %n, 1
  %f2 = call ulong(ulong) * %fib(ulong %n2)
  %f1 = call ulong(ulong) * %fib(ulong %n1)
  %result = add ulong %f2, %f1
  ret ulong %result
end

ulong "realmain"(int %argc, sbyte ** %argv)
begin
  seteq int %argc, 2      ; {bool}:0
  br bool %0, label %HasArg, label %Continue
HasArg:
  ; %n1 = atoi(argv[1])
  %n1 = add int 1, 1
  br label %Continue

Continue:
  %n = phi int [%n1, %HasArg], [1, %0]
  %N = cast int %n to ulong
  %F = call ulong(ulong) *%fib(ulong %N)
  ret ulong %F
end

ulong "trampoline"(ulong %n, ulong(ulong)* %fibfunc)
begin
  %F = call ulong(ulong) *%fibfunc(ulong %n)
  ret ulong %F
end

int "main"()
begin
  %Result = call ulong %trampoline(ulong 10, ulong(ulong) *%fib)
  %Result = cast ulong %Result to int
  ret int %Result
end