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Commit14cca1b

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Use static inline functions for float <-> Datum conversions.
Now that we are OK with using static inline functions, we can use themto avoid function call overhead of pass-by-val versions of Float4GetDatum,DatumGetFloat8, and Float8GetDatum. Those functions are only a few CPUinstructions long, but they could not be written into macros previously,because we need a local union variable for the conversion.I kept the pass-by-ref versions as regular functions. They are very simpletoo, but they call palloc() anyway, so shaving a few instructions from thefunction call doesn't seem so important there.Discussion: <dbb82a4a-2c15-ba27-dd0a-009d2aa72b77@iki.fi>
1 parent0e0f43d commit14cca1b

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2 files changed

+67
-59
lines changed

2 files changed

+67
-59
lines changed

‎src/backend/utils/fmgr/fmgr.c

Lines changed: 6 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -2126,10 +2126,7 @@ fmgr(Oid procedureId,...)
21262126
*
21272127
* int8, float4, and float8 can be passed by value if Datum is wide enough.
21282128
* (For backwards-compatibility reasons, we allow pass-by-ref to be chosen
2129-
* at compile time even if pass-by-val is possible.) For the float types,
2130-
* we need a support routine even if we are passing by value, because many
2131-
* machines pass int and float function parameters/results differently;
2132-
* so we need to play weird games with unions.
2129+
* at compile time even if pass-by-val is possible.)
21332130
*
21342131
* Note: there is only one switch controlling the pass-by-value option for
21352132
* both int8 and float8; this is to avoid making things unduly complicated
@@ -2149,77 +2146,29 @@ Int64GetDatum(int64 X)
21492146
}
21502147
#endif/* USE_FLOAT8_BYVAL */
21512148

2149+
#ifndefUSE_FLOAT4_BYVAL
2150+
21522151
Datum
21532152
Float4GetDatum(float4X)
21542153
{
2155-
#ifdefUSE_FLOAT4_BYVAL
2156-
union
2157-
{
2158-
float4value;
2159-
int32retval;
2160-
}myunion;
2161-
2162-
myunion.value=X;
2163-
returnSET_4_BYTES(myunion.retval);
2164-
#else
21652154
float4*retval= (float4*)palloc(sizeof(float4));
21662155

21672156
*retval=X;
21682157
returnPointerGetDatum(retval);
2169-
#endif
21702158
}
2159+
#endif
21712160

2172-
#ifdefUSE_FLOAT4_BYVAL
2173-
2174-
float4
2175-
DatumGetFloat4(DatumX)
2176-
{
2177-
union
2178-
{
2179-
int32value;
2180-
float4retval;
2181-
}myunion;
2182-
2183-
myunion.value=GET_4_BYTES(X);
2184-
returnmyunion.retval;
2185-
}
2186-
#endif/* USE_FLOAT4_BYVAL */
2161+
#ifndefUSE_FLOAT8_BYVAL
21872162

21882163
Datum
21892164
Float8GetDatum(float8X)
21902165
{
2191-
#ifdefUSE_FLOAT8_BYVAL
2192-
union
2193-
{
2194-
float8value;
2195-
int64retval;
2196-
}myunion;
2197-
2198-
myunion.value=X;
2199-
returnSET_8_BYTES(myunion.retval);
2200-
#else
22012166
float8*retval= (float8*)palloc(sizeof(float8));
22022167

22032168
*retval=X;
22042169
returnPointerGetDatum(retval);
2205-
#endif
22062170
}
2207-
2208-
#ifdefUSE_FLOAT8_BYVAL
2209-
2210-
float8
2211-
DatumGetFloat8(DatumX)
2212-
{
2213-
union
2214-
{
2215-
int64value;
2216-
float8retval;
2217-
}myunion;
2218-
2219-
myunion.value=GET_8_BYTES(X);
2220-
returnmyunion.retval;
2221-
}
2222-
#endif/* USE_FLOAT8_BYVAL */
2171+
#endif
22232172

22242173

22252174
/*-------------------------------------------------------------------------

‎src/include/postgres.h

Lines changed: 61 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -656,6 +656,14 @@ extern Datum Int64GetDatum(int64 X);
656656
#defineUInt64GetDatum(X) Int64GetDatum((int64) (X))
657657
#endif
658658

659+
/*
660+
* Float <-> Datum conversions
661+
*
662+
* These have to be implemented as inline functions rather than macros, when
663+
* passing by value, because many machines pass int and float function
664+
* parameters/results differently; so we need to play weird games with unions.
665+
*/
666+
659667
/*
660668
* DatumGetFloat4
661669
*Returns 4-byte floating point value of a datum.
@@ -664,7 +672,18 @@ extern Datum Int64GetDatum(int64 X);
664672
*/
665673

666674
#ifdefUSE_FLOAT4_BYVAL
667-
externfloat4DatumGetFloat4(DatumX);
675+
staticinlinefloat4
676+
DatumGetFloat4(DatumX)
677+
{
678+
union
679+
{
680+
int32value;
681+
float4retval;
682+
}myunion;
683+
684+
myunion.value=GET_4_BYTES(X);
685+
returnmyunion.retval;
686+
}
668687
#else
669688
#defineDatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X)))
670689
#endif
@@ -676,8 +695,22 @@ extern float4 DatumGetFloat4(Datum X);
676695
* Note: if float4 is pass by reference, this function returns a reference
677696
* to palloc'd space.
678697
*/
698+
#ifdefUSE_FLOAT4_BYVAL
699+
staticinlineDatum
700+
Float4GetDatum(float4X)
701+
{
702+
union
703+
{
704+
float4value;
705+
int32retval;
706+
}myunion;
679707

708+
myunion.value=X;
709+
returnSET_4_BYTES(myunion.retval);
710+
}
711+
#else
680712
externDatumFloat4GetDatum(float4X);
713+
#endif
681714

682715
/*
683716
* DatumGetFloat8
@@ -687,7 +720,18 @@ extern Datum Float4GetDatum(float4 X);
687720
*/
688721

689722
#ifdefUSE_FLOAT8_BYVAL
690-
externfloat8DatumGetFloat8(DatumX);
723+
staticinlinefloat8
724+
DatumGetFloat8(DatumX)
725+
{
726+
union
727+
{
728+
int64value;
729+
float8retval;
730+
}myunion;
731+
732+
myunion.value=GET_8_BYTES(X);
733+
returnmyunion.retval;
734+
}
691735
#else
692736
#defineDatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X)))
693737
#endif
@@ -700,7 +744,22 @@ extern float8 DatumGetFloat8(Datum X);
700744
* to palloc'd space.
701745
*/
702746

747+
#ifdefUSE_FLOAT8_BYVAL
748+
staticinlineDatum
749+
Float8GetDatum(float8X)
750+
{
751+
union
752+
{
753+
float8value;
754+
int64retval;
755+
}myunion;
756+
757+
myunion.value=X;
758+
returnSET_8_BYTES(myunion.retval);
759+
}
760+
#else
703761
externDatumFloat8GetDatum(float8X);
762+
#endif
704763

705764

706765
/*

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