Backport qemu/qemu@75b208c

target/i386: fix operand order for PDEP and PEXT

For PDEP and PEXT, the mask is provided in the memory (mod+r/m)
operand, and therefore is loaded in s->T0 by gen_ldst_modrm.
The source is provided in the second source operand (VEX.vvvv)
and therefore is loaded in s->T1. Fix the order in which
they are passed to the helpers.

qemu/target/i386/translate.c

@@ -4219,14 +4219,14 @@ static void gen_sse(CPUX86State *env, DisasContext *s, int b,
                 }
                 ot = mo_64_32(s->dflag);
                 gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 0);
-                /* Note that by zero-extending the mask operand, we
+                /* Note that by zero-extending the source operand, we
                    automatically handle zero-extending the result.  */
                 if (ot == MO_64) {
                     tcg_gen_mov_tl(tcg_ctx, s->T1, tcg_ctx->cpu_regs[s->vex_v]);
                 } else {
                     tcg_gen_ext32u_tl(tcg_ctx, s->T1, tcg_ctx->cpu_regs[s->vex_v]);
                 }
-                gen_helper_pdep(tcg_ctx, tcg_ctx->cpu_regs[reg], s->T0, s->T1);
+                gen_helper_pdep(tcg_ctx, tcg_ctx->cpu_regs[reg], s->T1, s->T0);
                 break;
 
             case 0x2f5: /* pext Gy, By, Ey */
@@ -4237,14 +4237,14 @@ static void gen_sse(CPUX86State *env, DisasContext *s, int b,
                 }
                 ot = mo_64_32(s->dflag);
                 gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 0);
-                /* Note that by zero-extending the mask operand, we
+                /* Note that by zero-extending the source operand, we
                    automatically handle zero-extending the result.  */
                 if (ot == MO_64) {
                     tcg_gen_mov_tl(tcg_ctx, s->T1, tcg_ctx->cpu_regs[s->vex_v]);
                 } else {
                     tcg_gen_ext32u_tl(tcg_ctx, s->T1, tcg_ctx->cpu_regs[s->vex_v]);
                 }
-                gen_helper_pext(tcg_ctx, tcg_ctx->cpu_regs[reg], s->T0, s->T1);
+                gen_helper_pext(tcg_ctx, tcg_ctx->cpu_regs[reg], s->T1, s->T0);
                 break;
 
             case 0x1f6: /* adcx Gy, Ey */