Hi,
The following arbitrary example makes the code generators to get stuck
(llvmc won't return from command line, Jit won't return from function
call)
Basically it is a CFG with circles, (the function will return by
comparing a branch counter to a threshold on runtime - see the
"Brancher" blocks below)
Any idea what goes wrong? Is it a bug in llvm ?
; ModuleID = 'TestModule!'
define double @fn1(i8*, i64) {
Entry:
%BranchCounter = alloca i32 ; <i32*> [#uses=7]
store i32 0, i32* %BranchCounter
%Vars = alloca double, i32 3 ; <double*> [#uses=3]
%DoubleVar = getelementptr inbounds double* %Vars, i32 0 ; <double*> [#uses=6]
store double 0xC031AD5A40000000, double* %DoubleVar
%DoubleVar1 = getelementptr inbounds double* %Vars, i32 1 ;
<double*> [#uses=1]
store double 0xC055A9E9E0000000, double* %DoubleVar1
%DoubleVar2 = getelementptr inbounds double* %Vars, i32 2 ;
<double*> [#uses=4]
store double 0xC0495B8A80000000, double* %DoubleVar2
br label %Brancher
Exit: ; preds =
%Brancher7, %Brancher4, %Brancher
%2 = load double* %DoubleVar ; <double> [#uses=1]
ret double %2
Body: ; preds = %Brancher
%3 = srem i64 30, %1 ; <i64> [#uses=1]
%4 = getelementptr inbounds i8* %0, i64 %3 ; <i8*> [#uses=1]
%5 = load i8* %4 ; <i8> [#uses=1]
%PeekResult = uitofp i8 %5 to double ; <double> [#uses=0]
%6 = load double* %DoubleVar2 ; <double> [#uses=1]
store double 0x40619C4E80000000, double* %DoubleVar
%7 = srem i64 178, %1 ; <i64> [#uses=1]
%8 = getelementptr inbounds i8* %0, i64 %7 ; <i8*> [#uses=1]
%9 = load i8* %8 ; <i8> [#uses=1]
%PeekResult9 = uitofp i8 %9 to double ; <double> [#uses=0]
store double %6, double* %DoubleVar
%10 = load double* %DoubleVar2 ; <double> [#uses=0]
%11 = load double* %DoubleVar ; <double> [#uses=0]
br i1 false, label %Brancher7, label %Brancher4
Brancher: ; preds = %Entry
%12 = load i32* %BranchCounter ; <i32> [#uses=1]
%"BrCounter++" = add i32 %12, 1 ; <i32> [#uses=2]
store i32 %"BrCounter++", i32* %BranchCounter
%13 = icmp ult i32 %"BrCounter++", 10 ; <i1> [#uses=1]
br i1 %13, label %Body, label %Exit
Body3: ; preds = %Brancher4
%14 = srem i64 40, %1 ; <i64> [#uses=1]
%15 = getelementptr inbounds i8* %0, i64 %14 ; <i8*> [#uses=1]
%16 = load i8* %15 ; <i8> [#uses=1]
%PeekResult10 = uitofp i8 %16 to double ; <double> [#uses=2]
%17 = fsub double 0xC058173FC0000000, %PeekResult10 ; <double> [#uses=1]
store double %PeekResult10, double* %DoubleVar2
%18 = fsub double 0x406AB76488000000, %17 ; <double> [#uses=1]
%19 = fdiv double %18, 0x4068C87680000000 ; <double> [#uses=0]
br label %Brancher4
Brancher4: ; preds = %Body6,
%Body3, %Body
%20 = load i32* %BranchCounter ; <i32> [#uses=1]
%"BrCounter++5" = add i32 %20, 1 ; <i32> [#uses=2]
store i32 %"BrCounter++5", i32* %BranchCounter
%21 = icmp ult i32 %"BrCounter++5", 10 ; <i1> [#uses=1]
br i1 %21, label %Body3, label %Exit
Body6: ; preds = %Brancher7
%22 = load double* %DoubleVar ; <double> [#uses=3]
%23 = srem i64 7118, %1 ; <i64> [#uses=1]
%24 = getelementptr inbounds i8* %0, i64 %23 ; <i8*> [#uses=1]
%25 = load i8* %24 ; <i8> [#uses=1]
%PeekResult11 = uitofp i8 %25 to double ; <double> [#uses=0]
%26 = fsub double %22, %22 ; <double> [#uses=0]
%27 = fcmp oeq double 0xC04FBB2E40000000, %22 ; <i1> [#uses=1]
br i1 %27, label %Brancher4, label %Brancher7
Brancher7: ; preds = %Body6, %Body
%28 = load i32* %BranchCounter ; <i32> [#uses=1]
%"BrCounter++8" = add i32 %28, 1 ; <i32> [#uses=2]
store i32 %"BrCounter++8", i32* %BranchCounter
%29 = icmp ult i32 %"BrCounter++8", 10 ; <i1> [#uses=1]
br i1 %29, label %Body6, label %Exit
}