*** ./sim/ppc/altivec.igen.ori	Fri May  2 14:14:43 2008
--- ./sim/ppc/altivec.igen	Fri May  2 14:56:53 2008
*************** unsigned32::model-function::altivec_unsi
*** 1634,1645 ****
  
  0.4,6.VS,11.VA,16.VB,21.VC,26.43:VX:av:vperm %VD, %VA, %VB, %VC:Vector Permute
  	int i, who;
  	for (i = 0; i < 16; i++) {
  	  who = (*vC).b[AV_BINDEX(i)] & 0x1f;
  	  if (who & 0x10)
! 	    (*vS).b[AV_BINDEX(i)] = (*vB).b[AV_BINDEX(who & 0xf)];
  	  else
! 	    (*vS).b[AV_BINDEX(i)] = (*vA).b[AV_BINDEX(who & 0xf)];
  	}
  	PPC_INSN_VR(VS_BITMASK, VA_BITMASK | VB_BITMASK | VC_BITMASK);
  
--- 1634,1650 ----
  
  0.4,6.VS,11.VA,16.VB,21.VC,26.43:VX:av:vperm %VD, %VA, %VB, %VC:Vector Permute
  	int i, who;
+ 	/* The permutation vector might have us read into the source vectors
+ 	   back at positions before the iteration index, so we must latch the
+ 	   sources to prevent early-clobbering in case the destination vector
+ 	   is the same as one of them.  */
+ 	vreg myvA = (*vA), myvB = (*vB);
  	for (i = 0; i < 16; i++) {
  	  who = (*vC).b[AV_BINDEX(i)] & 0x1f;
  	  if (who & 0x10)
! 	    (*vS).b[AV_BINDEX(i)] = myvB.b[AV_BINDEX(who & 0xf)];
  	  else
! 	    (*vS).b[AV_BINDEX(i)] = myvA.b[AV_BINDEX(who & 0xf)];
  	}
  	PPC_INSN_VR(VS_BITMASK, VA_BITMASK | VB_BITMASK | VC_BITMASK);