Fix inline asm in dscal: mark x, x1 as clobbered. Fixes #2408

bartoldeman · bartoldeman · commit 7ea5e07d1cb5 · 2020-02-12T14:11:44.000Z
The leaq instructions in dscal_kernel_inc_8 modify x and x1 so they
must be declared as input/output constraints, otherwise the compiler
may assume the corresponding registers are not modified.
diff --git a/kernel/x86_64/dscal.c b/kernel/x86_64/dscal.c
@@ -136,10 +136,10 @@ static void dscal_kernel_inc_8(BLASLONG n, FLOAT *alpha, FLOAT *x, BLASLONG inc_
 	"jnz    1b					    \n\t"
 
         :
-          "+r" (n)      // 0
+          "+r" (n),     // 0
+          "+r" (x),     // 1
+          "+r" (x1)     // 2
         :
-          "r" (x),      // 1
-          "r" (x1),     // 2
           "r" (alpha),  // 3
           "r" (inc_x),  // 4
           "r" (inc_x3)  // 5

Original file line number	Diff line number	Diff line change
`@@ -136,10 +136,10 @@ static void dscal_kernel_inc_8(BLASLONG n, FLOAT alpha, FLOAT x, BLASLONG inc_`
`136`	`136`	`"jnz 1b \n\t"`
`137`	`137`
`138`	`138`	`:`
`139`		`- "+r" (n) // 0`
	`139`	`+ "+r" (n), // 0`
	`140`	`+ "+r" (x), // 1`
	`141`	`+ "+r" (x1) // 2`
`140`	`142`	`:`
`141`		`- "r" (x), // 1`
`142`		`- "r" (x1), // 2`
`143`	`143`	`"r" (alpha), // 3`
`144`	`144`	`"r" (inc_x), // 4`
`145`	`145`	`"r" (inc_x3) // 5`