[LLVMdev] -instcombine broken with fastcall

[Arnaud Bergeron]

I found this with LLVM 2.3 and reproduced with svn as of about thirty
minutes ago and they both fail in the same way.

If you run this code through opt -instcombine

define fastcc i64 @fibo(i64) {
	switch i64 %0, label %2 [
		i64 0, label %8
		i64 1, label %8
	]

; <label>:2		; preds = %1
	%3 = sub i64 %0, 1		; <i64> [#uses=1]
	%4 = call i64 @fibo(i64 %3)		; <i64> [#uses=1]
	%5 = sub i64 %0, 2		; <i64> [#uses=1]
	%6 = call i64 @fibo(i64 %5)		; <i64> [#uses=1]
	%7 = add i64 %4, %6		; <i64> [#uses=1]
	ret i64 %7

; <label>:8		; preds = %1, %1
	ret i64 1
}

you get this crap back

define fastcc i64 @fibo(i64) {
	switch i64 %0, label %2 [
		i64 0, label %4
		i64 1, label %4
	]

; <label>:2		; preds = %1
	store i1 true, i1* undef
	store i1 true, i1* undef
	%3 = add i64 undef, undef		; <i64> [#uses=1]
	ret i64 %3

; <label>:4		; preds = %1, %1
	ret i64 1
}

(which, called in a program gives an instant bus error)

Arnaud