Commit5b63050

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Skip memcpy(x, x) in qunique().

It has undefined behavior. Follow the precedent of commit9a9473f. No back-patch, since themaster branch alone has this function.Discussion:https://postgr.es/m/20191229070221.GA13873@gust.leadboat.com

1 parentfac1c04 commit5b63050Copy full SHA for 5b63050

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Lines changed: 6 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -30,8 +30,9 @@ qunique(void *array, size_t elements, size_t width,`
`30`	`30`
`31`	`31`	`for (i=1,j=0;i<elements;++i)`
`32`	`32`	`{`
`33`		`-if (compare(bytes+iwidth,bytes+jwidth)!=0)`
`34`		`-memcpy(bytes+++jwidth,bytes+iwidth,width);`
	`33`	`+if (compare(bytes+iwidth,bytes+jwidth)!=0&&`
	`34`	`+++j!=i)`
	`35`	`+memcpy(bytes+jwidth,bytes+iwidth,width);`
`35`	`36`	`}`
`36`	`37`
`37`	`38`	`returnj+1;`
`@@ -55,8 +56,9 @@ qunique_arg(void *array, size_t elements, size_t width,`
`55`	`56`
`56`	`57`	`for (i=1,j=0;i<elements;++i)`
`57`	`58`	`{`
`58`		`-if (compare(bytes+iwidth,bytes+jwidth,arg)!=0)`
`59`		`-memcpy(bytes+++jwidth,bytes+iwidth,width);`
	`59`	`+if (compare(bytes+iwidth,bytes+jwidth,arg)!=0&&`
	`60`	`+++j!=i)`
	`61`	`+memcpy(bytes+jwidth,bytes+iwidth,width);`
`60`	`62`	`}`
`61`	`63`
`62`	`64`	`returnj+1;`

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