HiPE bug with comparison of floats with integers

Paul Guyot <>
Mon Jan 31 10:41:39 CET 2011


Hello,

There is a bug in HiPE compilation with the comparison of floats with integers.
This bug happens with the following two functions:

------
-module(hipe_zero).
-export([f/1, g/2]).

f(X) ->
    Y = X / 2,
    Y == 0.

g(X, Z) ->
    Y = X / 2,
    case Z of
        test when Y == 0 -> test_zero;
        test -> test_non_zero;
        other -> other
    end.
------

Beam will evaluate hipe_zero:f(0) and hipe_zero:f(0.0) to true, while HiPE will evaluate hipe_zero:f(0) and hipe_zero:f(0.0) to false. HiPE properly evaluates hipe_zero:f/1 to true if passed {icode_inline_bifs, false}. However, not inlining the '==' bif just masks the bug as HiPE does not properly evaluate hipe_zero:g(0, test) to test_zero.

Paul
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