[src/trunk]: src/external/gpl3/gcc/dist/gcc/config/i386 Apply upstream patch:

[maya <maya%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6f7495c1cf67
branches:  trunk
changeset: 825724:6f7495c1cf67
user:      maya <maya%NetBSD.org@localhost>
date:      Fri Jul 28 22:23:05 2017 +0000

description:
Apply upstream patch:
Incorrect codegen from rdseed intrinsic use (CVE-2017-11671)

We should not expand call arguments in between flags reg setting and
flags reg using instructions, as it may expand with flags reg
clobbering insn (ADD in this case).

Attached patch moves expansion out of the link. Also, change
zero-extension to non-flags reg clobbering sequence in case we perform
zero-extension with and.

2017-03-25  Uros Bizjak  <ubizjak%gmail.com@localhost>

diffstat:

 external/gpl3/gcc/dist/gcc/config/i386/i386.c |  30 +++++++++++++++++++-------
 1 files changed, 22 insertions(+), 8 deletions(-)

diffs (68 lines):

diff -r 1337e31fdb8a -r 6f7495c1cf67 external/gpl3/gcc/dist/gcc/config/i386/i386.c
--- a/external/gpl3/gcc/dist/gcc/config/i386/i386.c     Fri Jul 28 19:31:59 2017 +0000
+++ b/external/gpl3/gcc/dist/gcc/config/i386/i386.c     Fri Jul 28 22:23:05 2017 +0000
@@ -39529,9 +39529,6 @@
       mode0 = DImode;
 
 rdrand_step:
-      op0 = gen_reg_rtx (mode0);
-      emit_insn (GEN_FCN (icode) (op0));
-
       arg0 = CALL_EXPR_ARG (exp, 0);
       op1 = expand_normal (arg0);
       if (!address_operand (op1, VOIDmode))
@@ -39539,6 +39536,10 @@
          op1 = convert_memory_address (Pmode, op1);
          op1 = copy_addr_to_reg (op1);
        }
+
+      op0 = gen_reg_rtx (mode0);
+      emit_insn (GEN_FCN (icode) (op0));
+
       emit_move_insn (gen_rtx_MEM (mode0, op1), op0);
 
       op1 = gen_reg_rtx (SImode);
@@ -39547,8 +39548,20 @@
       /* Emit SImode conditional move.  */
       if (mode0 == HImode)
        {
-         op2 = gen_reg_rtx (SImode);
-         emit_insn (gen_zero_extendhisi2 (op2, op0));
+         if (TARGET_ZERO_EXTEND_WITH_AND
+             && optimize_function_for_speed_p (cfun))
+           {
+             op2 = force_reg (SImode, const0_rtx);
+
+             emit_insn (gen_movstricthi
+                        (gen_lowpart (HImode, op2), op0));
+           }
+         else
+           {
+             op2 = gen_reg_rtx (SImode);
+
+             emit_insn (gen_zero_extendhisi2 (op2, op0));
+           }
        }
       else if (mode0 == SImode)
        op2 = op0;
@@ -39580,9 +39593,6 @@
       mode0 = DImode;
 
 rdseed_step:
-      op0 = gen_reg_rtx (mode0);
-      emit_insn (GEN_FCN (icode) (op0));
-
       arg0 = CALL_EXPR_ARG (exp, 0);
       op1 = expand_normal (arg0);
       if (!address_operand (op1, VOIDmode))
@@ -39590,6 +39600,10 @@
          op1 = convert_memory_address (Pmode, op1);
          op1 = copy_addr_to_reg (op1);
        }
+
+      op0 = gen_reg_rtx (mode0);
+      emit_insn (GEN_FCN (icode) (op0));
+
       emit_move_insn (gen_rtx_MEM (mode0, op1), op0);
 
       op2 = gen_reg_rtx (QImode);