cf. <https://github.com/libjpeg-turbo/libjpeg-turbo/commit/
8b2c04f774d18e05e321ee67a9a38b4d7e84f168> "Fix x86-64 ABI conformance issue in
SIMD code":
--- simd/jcclrss2-64.asm
+++ simd/jcclrss2-64.asm
@@ -50,14 +50,14 @@
 	collect_args
 	push	rbx
 
-	mov	rcx, r10
+	mov	ecx, r10d
 	test	rcx,rcx
 	jz	near .return
 
 	push	rcx
 
 	mov rsi, r12
-	mov rcx, r13
+	mov ecx, r13d
 	mov	rdi, JSAMPARRAY [rsi+0*SIZEOF_JSAMPARRAY]
 	mov	rbx, JSAMPARRAY [rsi+1*SIZEOF_JSAMPARRAY]
 	mov	rdx, JSAMPARRAY [rsi+2*SIZEOF_JSAMPARRAY]
--- simd/jcgryss2-64.asm
+++ simd/jcgryss2-64.asm
@@ -50,14 +50,14 @@
 	collect_args
 	push	rbx
 
-	mov	rcx, r10
+	mov	ecx, r10d
 	test	rcx,rcx
 	jz	near .return
 
 	push	rcx
 
 	mov rsi, r12
-	mov rcx, r13
+	mov ecx, r13d
 	mov	rdi, JSAMPARRAY [rsi+0*SIZEOF_JSAMPARRAY]
 	lea	rdi, [rdi+rcx*SIZEOF_JSAMPROW]
 
--- simd/jcqnts2f-64.asm
+++ simd/jcqnts2f-64.asm
@@ -50,7 +50,7 @@
 	packsswb xmm7,xmm7		; xmm7 = PB_CENTERJSAMPLE (0x808080..)
 
 	mov rsi, r10
-	mov	rax, r11
+	mov	eax, r11d
 	mov rdi, r12
 	mov	rcx, DCTSIZE/2
 .convloop:
--- simd/jcqnts2i-64.asm
+++ simd/jcqnts2i-64.asm
@@ -50,7 +50,7 @@
 	psllw	xmm7,7			; xmm7={0xFF80 0xFF80 0xFF80 0xFF80 ..}
 
 	mov rsi, r10
-	mov rax, r11
+	mov eax, r11d
 	mov rdi, r12
 	mov	rcx, DCTSIZE/4
 .convloop:
--- simd/jcsamss2-64.asm
+++ simd/jcsamss2-64.asm
@@ -49,11 +49,11 @@
 	mov	rbp,rsp
 	collect_args
 
-	mov rcx, r13
+	mov ecx, r13d
 	shl	rcx,3			; imul rcx,DCTSIZE (rcx = output_cols)
 	jz	near .return
 
-	mov rdx, r10
+	mov edx, r10d
 
 	; -- expand_right_edge
 
@@ -90,7 +90,7 @@
 
 	; -- h2v1_downsample
 
-	mov	rax, r12	; rowctr
+	mov	eax, r12d	; rowctr
 	test	eax,eax
 	jle	near .return
 
@@ -193,11 +193,11 @@
 	mov	rbp,rsp
 	collect_args
 
-	mov	rcx, r13
+	mov	rcx, r13
 	shl	rcx,3			; imul rcx,DCTSIZE (rcx = output_cols)
 	jz	near .return
 
-	mov	rdx, r10
+	mov	edx, r10d
 
 	; -- expand_right_edge
 
@@ -234,7 +234,7 @@
 
 	; -- h2v2_downsample
 
-	mov	rax, r12	; rowctr
+	mov	eax, r12d	; rowctr
 	test	rax,rax
 	jle	near .return
 
--- simd/jdclrss2-64.asm
+++ simd/jdclrss2-64.asm
@@ -52,14 +52,14 @@
 	collect_args
 	push	rbx
 
-	mov	rcx, r10	; num_cols
+	mov	ecx, r10d	; num_cols
 	test	rcx,rcx
 	jz	near .return
 
 	push	rcx
 
 	mov	rdi, r11
-	mov	rcx, r12
+	mov	ecx, r12d
 	mov	rsi, JSAMPARRAY [rdi+0*SIZEOF_JSAMPARRAY]
 	mov	rbx, JSAMPARRAY [rdi+1*SIZEOF_JSAMPARRAY]
 	mov	rdx, JSAMPARRAY [rdi+2*SIZEOF_JSAMPARRAY]
--- simd/jdmrgss2-64.asm
+++ simd/jdmrgss2-64.asm
@@ -52,14 +52,14 @@
 	collect_args
 	push	rbx
 
-	mov	rcx, r10	; col
+	mov	ecx, r10d	; col
 	test	rcx,rcx
 	jz	near .return
 
 	push	rcx
 
 	mov	rdi, r11
-	mov	rcx, r12
+	mov	ecx, r12d
 	mov	rsi, JSAMPARRAY [rdi+0*SIZEOF_JSAMPARRAY]
 	mov	rbx, JSAMPARRAY [rdi+1*SIZEOF_JSAMPARRAY]
 	mov	rdx, JSAMPARRAY [rdi+2*SIZEOF_JSAMPARRAY]
@@ -455,10 +455,10 @@
 	collect_args
 	push	rbx
 
-	mov	rax, r10
+	mov	eax, r10d
 
 	mov	rdi, r11
-	mov	rcx, r12
+	mov	ecx, r12d
 	mov	rsi, JSAMPARRAY [rdi+0*SIZEOF_JSAMPARRAY]
 	mov	rbx, JSAMPARRAY [rdi+1*SIZEOF_JSAMPARRAY]
 	mov	rdx, JSAMPARRAY [rdi+2*SIZEOF_JSAMPARRAY]
--- simd/jdsamss2-64.asm
+++ simd/jdsamss2-64.asm
@@ -67,7 +67,7 @@
 	mov	rbp,rsp
 	collect_args
 
-	mov	rax, r11  ; colctr
+	mov	eax, r11d  ; colctr
 	test	rax,rax
 	jz	near .return
 
@@ -214,7 +214,7 @@
 	collect_args
 	push	rbx
 
-	mov	rax, r11  ; colctr
+	mov	eax, r11d  ; colctr
 	test	rax,rax
 	jz	near .return
 
@@ -506,7 +506,7 @@
 	mov	rbp,rsp
 	collect_args
 
-	mov	rdx, r11
+	mov	edx, r11d
 	add	rdx, byte (2*SIZEOF_XMMWORD)-1
 	and	rdx, byte -(2*SIZEOF_XMMWORD)
 	jz	near .return
@@ -596,7 +596,7 @@
 	collect_args
 	push	rbx
 
-	mov	rdx, r11
+	mov	edx, r11d
 	add	rdx, byte (2*SIZEOF_XMMWORD)-1
 	and	rdx, byte -(2*SIZEOF_XMMWORD)
 	jz	near .return
--- simd/jiss2flt-64.asm
+++ simd/jiss2flt-64.asm
@@ -326,7 +326,7 @@
 	mov	rax, [original_rbp]
 	lea	rsi, [workspace]			; FAST_FLOAT * wsptr
 	mov	rdi, r12	; (JSAMPROW *)
-	mov	rax, r13
+	mov	eax, r13d
 	mov	rcx, DCTSIZE/4				; ctr
 .rowloop:
 
--- simd/jiss2fst-64.asm
+++ simd/jiss2fst-64.asm
@@ -323,7 +323,7 @@
 
 	mov	rax, [original_rbp]
 	mov	rdi, r12	; (JSAMPROW *)
-	mov	rax, r13
+	mov	eax, r13d
 
 	; -- Even part
 
--- simd/jiss2int-64.asm
+++ simd/jiss2int-64.asm
@@ -515,7 +515,7 @@
 
 	mov	rax, [original_rbp]
 	mov	rdi, r12	; (JSAMPROW *)
-	mov	rax, r13
+	mov	eax, r13d
 
 	; -- Even part
 
--- simd/jiss2red-64.asm
+++ simd/jiss2red-64.asm
@@ -312,7 +312,7 @@
 
 	mov	rax, [original_rbp]
 	mov	rdi, r12	; (JSAMPROW *)
-	mov	rax, r13
+	mov	eax, r13d
 
 	; -- Even part
 
@@ -521,7 +521,7 @@
 	; ---- Pass 2: process rows, store into output array.
 
 	mov	rdi, r12	; (JSAMPROW *)
-	mov	rax, r13
+	mov	eax, r13d
 
 	; | input:| result:|
 	; | A0 B0 |        |