[LLVMdev] FP problems in different backends?

[Roman Levenstein]

Hi,

Here is yet another bug/miscompilation I've found while testing my
register allocator.

The compilation of the attached BC file fails on multiple backends, namely:
 ia64, mips, mipsel, alpha

The failures are different from backend to backend (wrong register
classes, wrong operand types, etc). Please, just try to compile using
the attached BC file. I guess, it is related to the FP support.

May be I'm testing in the wong way?
What I currently do is:
1) I compile the source file on my X86 machine, using the following options:
   llvm-gcc -O6 -c -emit-llvm -o obj/cf1.c.bc cf1.c

I get this disassembled ll file:
; ModuleID = 'cf1.c.bc'
target datalayout =
"e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
target triple = "i386-pc-linux-gnu"
@fl = external global float             ; <float*> [#uses=1]
@a = weak global i32 0          ; <i32*> [#uses=1]

define void @mai() nounwind {
entry:
        %tmp = load float* @fl, align 4         ; <float> [#uses=1]
        %tmp1 = fcmp une float %tmp, 0.000000e+00               ; <i1> [#uses=1]
        br i1 %tmp1, label %bb, label %UnifiedReturnBlock

bb:             ; preds = %entry
        store i32 10, i32* @a, align 4
        ret void

UnifiedReturnBlock:             ; preds = %entry
        ret void
}


2) I generate code from the BC file using these e.g. options:
   llc --regalloc=linearscan -f cf1.c.bc -march=ia64

Could it be that llvm-gcc produces a target specific BC file and takes
e.g. target specific FP implementation and representation into
account? If so, how can I produce a correct BC file for a given
target, e.g. mips and afterwards test it?

I also attach a very simple original C source file.

Can someone confirm these failures? Any ideas about what is wrong with
this input file?

-Roman
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