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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2017-03-25 03:01:17 +0100 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2017-11-18 13:54:54 +0100 |
| commit | 1c182507c3981aa20193c68d7cfd32d750b571cf (patch) | |
| tree | b0ec94c9cad3d457ffb7db679a070db729327450 /validation/optim/canonical-fcmp.c | |
| parent | 1fb139520881e9339589048c9c31dd1956a33ffb (diff) | |
| download | sparse-dev-1c182507c3981aa20193c68d7cfd32d750b571cf.tar.gz | |
fix support of floating-point compare
Comparision of floating-point values can't be done
like for integral values because of the possibility to have
NaNs which can't be ordered with normal values or even between
themselves.
The real difference appears once there is any "reasoning"
done with the result of the comparison. For example, once NaNs
are taken in account: "!(a < b)" and "(a >= b)" are not the same.
In fact the usual comparison operators must be reinterpreted
as implicitely first testing if any of the operand is a Nan
and return 'false' if it is the case. Thus "a < b" becomes
"!isnan(a) && !isnan(b) && (a < b)".
If we need to negate the comparison we get "!(a < b)" which
naturally becomes "isnan(a) || isnan(b) || (a >= b)".
We thus need two sets of operators for comparison of floats:
one for the "ordered" values (only true if neither operand
is a Nan) and one for the "values" (also true if either
operand is a NaN). A negation of the comparison switch from one
of the set to the other.
So, introduce another set of instructions for the comparison
of floats.
Note: the C standard requires that:
*) "x == x" is false if x is a NaN,
*) "x != x" is true if x is a NaN,
and this is coherent with "x != x" <-> "!(x == x)".
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Diffstat (limited to 'validation/optim/canonical-fcmp.c')
| -rw-r--r-- | validation/optim/canonical-fcmp.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/validation/optim/canonical-fcmp.c b/validation/optim/canonical-fcmp.c new file mode 100644 index 00000000..e3e758a9 --- /dev/null +++ b/validation/optim/canonical-fcmp.c @@ -0,0 +1,123 @@ +extern double g; + +int fcmp_eq(double a) { return (g == a); } +int fcmp_ne(double a) { return (g != a); } + +int fcmp_gt(double a) { return (g > a); } +int fcmp_ge(double a) { return (g >= a); } +int fcmp_le(double a) { return (g <= a); } +int fcmp_lt(double a) { return (g < a); } + +int nfcmp_ne(double a) { return !(g == a); } +int nfcmp_eq(double a) { return !(g != a); } + +int nfcmp_le(double a) { return !(g > a); } +int nfcmp_lt(double a) { return !(g >= a); } +int nfcmp_gt(double a) { return !(g <= a); } +int nfcmp_ge(double a) { return !(g < a); } + +/* + * check-name: canonical-cmp + * check-command: test-linearize -Wno-decl $file + * + * check-output-exclude: \$123, + * + * check-output-start +fcmp_eq: +.L0: + <entry-point> + load.64 %r1 <- 0[g] + fcmpoeq.32 %r3 <- %r1, %arg1 + ret.32 %r3 + + +fcmp_ne: +.L2: + <entry-point> + load.64 %r5 <- 0[g] + fcmpune.32 %r7 <- %r5, %arg1 + ret.32 %r7 + + +fcmp_gt: +.L4: + <entry-point> + load.64 %r9 <- 0[g] + fcmpogt.32 %r11 <- %r9, %arg1 + ret.32 %r11 + + +fcmp_ge: +.L6: + <entry-point> + load.64 %r13 <- 0[g] + fcmpoge.32 %r15 <- %r13, %arg1 + ret.32 %r15 + + +fcmp_le: +.L8: + <entry-point> + load.64 %r17 <- 0[g] + fcmpole.32 %r19 <- %r17, %arg1 + ret.32 %r19 + + +fcmp_lt: +.L10: + <entry-point> + load.64 %r21 <- 0[g] + fcmpolt.32 %r23 <- %r21, %arg1 + ret.32 %r23 + + +nfcmp_ne: +.L12: + <entry-point> + load.64 %r25 <- 0[g] + fcmpune.32 %r28 <- %r25, %arg1 + ret.32 %r28 + + +nfcmp_eq: +.L14: + <entry-point> + load.64 %r30 <- 0[g] + fcmpoeq.32 %r33 <- %r30, %arg1 + ret.32 %r33 + + +nfcmp_le: +.L16: + <entry-point> + load.64 %r35 <- 0[g] + fcmpule.32 %r38 <- %r35, %arg1 + ret.32 %r38 + + +nfcmp_lt: +.L18: + <entry-point> + load.64 %r40 <- 0[g] + fcmpult.32 %r43 <- %r40, %arg1 + ret.32 %r43 + + +nfcmp_gt: +.L20: + <entry-point> + load.64 %r45 <- 0[g] + fcmpugt.32 %r48 <- %r45, %arg1 + ret.32 %r48 + + +nfcmp_ge: +.L22: + <entry-point> + load.64 %r50 <- 0[g] + fcmpuge.32 %r53 <- %r50, %arg1 + ret.32 %r53 + + + * check-output-end + */ |