sha/asm/sha512p8-ppc.pl: improve POWER9 performance by ~10%.

Biggest part, ~7%, of improvement resulted from omitting constants'
table index increment in each round. And minor part from rescheduling
instructions. Apparently POWER9 (and POWER8) manage to dispatch
instructions more efficiently if they are laid down as if they have
no latency...

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6406)

crypto/sha/asm/sha512p8-ppc.pl

diff --git a/crypto/sha/asm/sha512p8-ppc.pl b/crypto/sha/asm/sha512p8-ppc.pl
index 7a8d435..e3f522c 100755
--- a/crypto/sha/asm/sha512p8-ppc.pl
+++ b/crypto/sha/asm/sha512p8-ppc.pl
@@ -37,8 +37,8 @@
 # build of sha512-ppc.pl, presented for reference.
 #
 #		POWER8		POWER9
-# SHA256	9.9 [15.8]	12.2 [12.5]
-# SHA512	6.3 [10.3]	7.7 [7.9]
+# SHA256	9.7 [15.8]	11.2 [12.5]
+# SHA512	6.1 [10.3]	7.0 [7.9]
 
 $flavour=shift;
 $output =shift;
@@ -79,7 +79,8 @@
 }
 
 $func="sha${bits}_block_p8";
-$FRAME=8*$SIZE_T;
+$LOCALS=8*$SIZE_T+8*16;
+$FRAME=$LOCALS+9*16+6*$SIZE_T;
 
 $sp ="r1";
 $toc="r2";
@@ -91,16 +92,17 @@
 $lrsave="r8";
 $offload="r11";
 $vrsave="r12";
-($x00,$x10,$x20,$x30,$x40,$x50,$x60,$x70)=map("r$_",(0,10,26..31));
- $x00=0 if ($flavour =~ /osx/);
+@I = ($x00,$x10,$x20,$x30,$x40,$x50,$x60,$x70)=map("r$_",(0,10,26..31));
+      $x00=0 if ($flavour =~ /osx/);
 
 @V=($A,$B,$C,$D,$E,$F,$G,$H)=map("v$_",(0..7));
-@X=map("v$_",(8..23));
-($Ki,$Func,$S0,$S1,$s0,$s1,$lemask)=map("v$_",(24..31));
+@X=map("v$_",(8..19,24..27));
+($Ki,$Func,$Sigma,$lemask)=map("v$_",(28..31));
 
 sub ROUND {
 my ($i,$a,$b,$c,$d,$e,$f,$g,$h)=@_;
 my $j=($i+1)%16;
+my $k=($i+2)%8;
 
 $code.=<<___		if ($i<15 && ($i%(16/$SZ))==(16/$SZ-1));
 	lvx_u		@X[$i+1],0,$inp		; load X[i] in advance
@@ -112,26 +114,30 @@
 $code.=<<___		if ($LENDIAN && $i<16 && ($i%(16/$SZ))==0);
 	vperm		@X[$i],@X[$i],@X[$i],$lemask
 ___
+$code.=<<___		if ($i>=15);
+	vshasigma${sz}	$Sigma,@X[($j+1)%16],0,0
+	vaddu${sz}m	@X[$j],@X[$j],$Sigma
+	vshasigma${sz}	$Sigma,@X[($j+14)%16],0,15
+	vaddu${sz}m	@X[$j],@X[$j],$Sigma
+	vaddu${sz}m	@X[$j],@X[$j],@X[($j+9)%16]
+___
 $code.=<<___;
-	`"vshasigma${sz}	$s0,@X[($j+1)%16],0,0"		if ($i>=15)`
-	vsel		$Func,$g,$f,$e		; Ch(e,f,g)
-	vshasigma${sz}	$S1,$e,1,15		; Sigma1(e)
 	vaddu${sz}m	$h,$h,@X[$i%16]		; h+=X[i]
-	vshasigma${sz}	$S0,$a,1,0		; Sigma0(a)
-	`"vshasigma${sz}	$s1,@X[($j+14)%16],0,15"	if ($i>=15)`
-	vaddu${sz}m	$h,$h,$Func		; h+=Ch(e,f,g)
-	vxor		$Func,$a,$b
-	`"vaddu${sz}m		@X[$j],@X[$j],@X[($j+9)%16]"	if ($i>=15)`
-	vaddu${sz}m	$h,$h,$S1		; h+=Sigma1(e)
-	vsel		$Func,$b,$c,$Func	; Maj(a,b,c)
+	vsel		$Func,$g,$f,$e		; Ch(e,f,g)
 	vaddu${sz}m	$g,$g,$Ki		; future h+=K[i]
+	vaddu${sz}m	$h,$h,$Func		; h+=Ch(e,f,g)
+	vshasigma${sz}	$Sigma,$e,1,15		; Sigma1(e)
+	vaddu${sz}m	$h,$h,$Sigma		; h+=Sigma1(e)
+	vxor		$Func,$a,$b
+	vsel		$Func,$b,$c,$Func	; Maj(a,b,c)
 	vaddu${sz}m	$d,$d,$h		; d+=h
-	vaddu${sz}m	$S0,$S0,$Func		; Sigma0(a)+Maj(a,b,c)
-	`"vaddu${sz}m		@X[$j],@X[$j],$s0"		if ($i>=15)`
-	lvx		$Ki,$idx,$Tbl		; load next K[i]
-	addi		$idx,$idx,16
-	vaddu${sz}m	$h,$h,$S0		; h+=Sigma0(a)+Maj(a,b,c)
-	`"vaddu${sz}m		@X[$j],@X[$j],$s1"		if ($i>=15)`
+	vshasigma${sz}	$Sigma,$a,1,0		; Sigma0(a)
+	vaddu${sz}m	$Sigma,$Sigma,$Func	; Sigma0(a)+Maj(a,b,c)
+	vaddu${sz}m	$h,$h,$Sigma		; h+=Sigma0(a)+Maj(a,b,c)
+	lvx		$Ki,@I[$k],$idx		; load next K[i]
+___
+$code.=<<___		if ($k == 7);
+	addi		$idx,$idx,0x80
 ___
 }
 
@@ -142,21 +148,13 @@
 .globl	$func
 .align	6
 $func:
-	$STU		$sp,-`($FRAME+21*16+6*$SIZE_T)`($sp)
+	$STU		$sp,-$FRAME($sp)
 	mflr		$lrsave
-	li		r10,`$FRAME+8*16+15`
-	li		r11,`$FRAME+8*16+31`
-	stvx		v20,r10,$sp		# ABI says so
+	li		r10,`$LOCALS+15`
+	li		r11,`$LOCALS+31`
+	stvx		v24,r10,$sp		# ABI says so
 	addi		r10,r10,32
 	mfspr		$vrsave,256
-	stvx		v21,r11,$sp
-	addi		r11,r11,32
-	stvx		v22,r10,$sp
-	addi		r10,r10,32
-	stvx		v23,r11,$sp
-	addi		r11,r11,32
-	stvx		v24,r10,$sp
-	addi		r10,r10,32
 	stvx		v25,r11,$sp
 	addi		r11,r11,32
 	stvx		v26,r10,$sp
@@ -169,26 +167,26 @@
 	addi		r11,r11,32
 	stvx		v30,r10,$sp
 	stvx		v31,r11,$sp
-	li		r11,-1
-	stw		$vrsave,`$FRAME+21*16-4`($sp)	# save vrsave
+	li		r11,-4096+255
+	stw		$vrsave,`$FRAME+6*$SIZE_T-4`($sp)	# save vrsave
 	li		$x10,0x10
-	$PUSH		r26,`$FRAME+21*16+0*$SIZE_T`($sp)
+	$PUSH		r26,`$FRAME-6*$SIZE_T`($sp)
 	li		$x20,0x20
-	$PUSH		r27,`$FRAME+21*16+1*$SIZE_T`($sp)
+	$PUSH		r27,`$FRAME-5*$SIZE_T`($sp)
 	li		$x30,0x30
-	$PUSH		r28,`$FRAME+21*16+2*$SIZE_T`($sp)
+	$PUSH		r28,`$FRAME-4*$SIZE_T`($sp)
 	li		$x40,0x40
-	$PUSH		r29,`$FRAME+21*16+3*$SIZE_T`($sp)
+	$PUSH		r29,`$FRAME-3*$SIZE_T`($sp)
 	li		$x50,0x50
-	$PUSH		r30,`$FRAME+21*16+4*$SIZE_T`($sp)
+	$PUSH		r30,`$FRAME-2*$SIZE_T`($sp)
 	li		$x60,0x60
-	$PUSH		r31,`$FRAME+21*16+5*$SIZE_T`($sp)
+	$PUSH		r31,`$FRAME-1*$SIZE_T`($sp)
 	li		$x70,0x70
-	$PUSH		$lrsave,`$FRAME+21*16+6*$SIZE_T+$LRSAVE`($sp)
+	$PUSH		$lrsave,`$FRAME+$LRSAVE`($sp)
 	mtspr		256,r11
 
 	bl		LPICmeup
-	addi		$offload,$sp,$FRAME+15
+	addi		$offload,$sp,`8*$SIZE_T+15`
 ___
 $code.=<<___		if ($LENDIAN);
 	li		$idx,8
@@ -222,9 +220,9 @@
 .align	5
 Loop:
 	lvx		$Ki,$x00,$Tbl
-	li		$idx,16
 	lvx_u		@X[0],0,$inp
 	addi		$inp,$inp,16
+	mr		$idx,$Tbl		# copy $Tbl
 	stvx		$A,$x00,$offload	# offload $A-$H
 	stvx		$B,$x10,$offload
 	stvx		$C,$x20,$offload
@@ -234,8 +232,7 @@
 	stvx		$G,$x60,$offload
 	stvx		$H,$x70,$offload
 	vaddu${sz}m	$H,$H,$Ki		# h+K[i]
-	lvx		$Ki,$idx,$Tbl
-	addi		$idx,$idx,16
+	lvx		$Ki,$x10,$Tbl
 ___
 for ($i=0;$i<16;$i++)	{ &ROUND($i,@V); unshift(@V,pop(@V)); }
 $code.=<<___;
@@ -268,10 +265,9 @@
 	bne		Loop
 ___
 $code.=<<___		if ($SZ==4);
-	lvx		@X[0],$idx,$Tbl
-	addi		$idx,$idx,16
+	lvx		@X[0],$x20,$idx
 	vperm		$A,$A,$B,$Ki		# pack the answer
-	lvx		@X[1],$idx,$Tbl
+	lvx		@X[1],$x30,$idx
 	vperm		$E,$E,$F,$Ki
 	vperm		$A,$A,$C,@X[0]
 	vperm		$E,$E,$G,@X[0]
@@ -291,19 +287,11 @@
 	stvx_u		$G,$x30,$ctx
 ___
 $code.=<<___;
-	li		r10,`$FRAME+8*16+15`
+	li		r10,`$LOCALS+15`
 	mtlr		$lrsave
-	li		r11,`$FRAME+8*16+31`
+	li		r11,`$LOCALS+31`
 	mtspr		256,$vrsave
-	lvx		v20,r10,$sp		# ABI says so
-	addi		r10,r10,32
-	lvx		v21,r11,$sp
-	addi		r11,r11,32
-	lvx		v22,r10,$sp
-	addi		r10,r10,32
-	lvx		v23,r11,$sp
-	addi		r11,r11,32
-	lvx		v24,r10,$sp
+	lvx		v24,r10,$sp		# ABI says so
 	addi		r10,r10,32
 	lvx		v25,r11,$sp
 	addi		r11,r11,32
@@ -317,13 +305,13 @@
 	addi		r11,r11,32
 	lvx		v30,r10,$sp
 	lvx		v31,r11,$sp
-	$POP		r26,`$FRAME+21*16+0*$SIZE_T`($sp)
-	$POP		r27,`$FRAME+21*16+1*$SIZE_T`($sp)
-	$POP		r28,`$FRAME+21*16+2*$SIZE_T`($sp)
-	$POP		r29,`$FRAME+21*16+3*$SIZE_T`($sp)
-	$POP		r30,`$FRAME+21*16+4*$SIZE_T`($sp)
-	$POP		r31,`$FRAME+21*16+5*$SIZE_T`($sp)
-	addi		$sp,$sp,`$FRAME+21*16+6*$SIZE_T`
+	$POP		r26,`$FRAME-6*$SIZE_T`($sp)
+	$POP		r27,`$FRAME-5*$SIZE_T`($sp)
+	$POP		r28,`$FRAME-4*$SIZE_T`($sp)
+	$POP		r29,`$FRAME-3*$SIZE_T`($sp)
+	$POP		r30,`$FRAME-2*$SIZE_T`($sp)
+	$POP		r31,`$FRAME-1*$SIZE_T`($sp)
+	addi		$sp,$sp,$FRAME
 	blr
 	.long		0
 	.byte		0,12,4,1,0x80,6,3,0