[gcc r14-6242] [APX NDD] Disable seg_prefixed memory usage for NDD add

[gcc r14-6242] [APX NDD] Disable seg_prefixed memory usage for NDD add

[Hongyu Wang]

https://gcc.gnu.org/g:d564198f960a2f5994dde3f6b83d7a62021e49c3

commit r14-6242-gd564198f960a2f5994dde3f6b83d7a62021e49c3
Author: Hongyu Wang <hongyu.wang@intel.com>
Date:   Mon Nov 13 18:49:07 2023 +0800

    [APX NDD] Disable seg_prefixed memory usage for NDD add
    
    NDD uses evex prefix, so when segment prefix is also applied, the instruction
    could excceed its 15byte limit, especially adding immediates. This could happen
    when "e" constraint accepts any UNSPEC_TPOFF/UNSPEC_NTPOFF constant and it will
    add the offset to segment register, which will be encoded using segment prefix.
    Disable those *POFF constant usage in NDD add alternatives with new constraint.
    
    gcc/ChangeLog:
    
            * config/i386/constraints.md (je): New constraint.
            * config/i386/i386-protos.h (x86_poff_operand_p): New function to
            check any *POFF constant in operand.
            * config/i386/i386.cc (x86_poff_operand_p): New prototype.
            * config/i386/i386.md (*add<mode>_1): Split out je alternative for add.

Diff:
---
 gcc/config/i386/constraints.md |  5 +++++
 gcc/config/i386/i386-protos.h  |  1 +
 gcc/config/i386/i386.cc        | 25 +++++++++++++++++++++++++
 gcc/config/i386/i386.md        |  8 ++++----
 4 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md
index cbee31fa40a..f4c3c3dd952 100644
--- a/gcc/config/i386/constraints.md
+++ b/gcc/config/i386/constraints.md
@@ -433,3 +433,8 @@
 
 (define_register_constraint  "jc"
  "TARGET_APX_EGPR && !TARGET_AVX ? GENERAL_GPR16 : GENERAL_REGS")
+
+(define_constraint  "je"
+  "@internal constant that do not allow any unspec global offsets"
+  (and (match_operand 0 "x86_64_immediate_operand")
+       (match_test "!x86_poff_operand_p (op)")))
diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h
index a9d0c568bba..7dfeb6af225 100644
--- a/gcc/config/i386/i386-protos.h
+++ b/gcc/config/i386/i386-protos.h
@@ -66,6 +66,7 @@ extern bool x86_extended_QIreg_mentioned_p (rtx_insn *);
 extern bool x86_extended_reg_mentioned_p (rtx);
 extern bool x86_extended_rex2reg_mentioned_p (rtx);
 extern bool x86_evex_reg_mentioned_p (rtx [], int);
+extern bool x86_poff_operand_p (rtx);
 extern bool x86_maybe_negate_const_int (rtx *, machine_mode);
 extern machine_mode ix86_cc_mode (enum rtx_code, rtx, rtx);
 
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 7c5cab4e2c6..8aa33aef7e1 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -23331,6 +23331,31 @@ x86_evex_reg_mentioned_p (rtx operands[], int nops)
   return false;
 }
 
+/* Return true when rtx operand does not contain any UNSPEC_*POFF related
+   constant to avoid APX_NDD instructions excceed encoding length limit.  */
+bool
+x86_poff_operand_p (rtx operand)
+{
+  if (GET_CODE (operand) == CONST)
+    {
+      rtx op = XEXP (operand, 0);
+      if (GET_CODE (op) == PLUS)
+	op = XEXP (op, 0);
+	
+      if (GET_CODE (op) == UNSPEC)
+	{
+	  int unspec = XINT (op, 1);
+	  return (unspec == UNSPEC_NTPOFF
+		  || unspec == UNSPEC_TPOFF
+		  || unspec == UNSPEC_DTPOFF
+		  || unspec == UNSPEC_GOTTPOFF
+		  || unspec == UNSPEC_GOTNTPOFF
+		  || unspec == UNSPEC_INDNTPOFF);
+	}
+    }
+  return false;
+}
+
 /* If profitable, negate (without causing overflow) integer constant
    of mode MODE at location LOC.  Return true in this case.  */
 bool
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 1e846183347..a1626121227 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -6418,10 +6418,10 @@
  "split_double_mode (<DWI>mode, &operands[0], 1, &operands[0], &operands[5]);")
 
 (define_insn "*add<mode>_1"
-  [(set (match_operand:SWI48 0 "nonimmediate_operand" "=rm,r,r,r,r,r")
+  [(set (match_operand:SWI48 0 "nonimmediate_operand" "=rm,r,r,r,r,r,r,r")
 	(plus:SWI48
-	  (match_operand:SWI48 1 "nonimmediate_operand" "%0,0,r,r,rm,r")
-	  (match_operand:SWI48 2 "x86_64_general_operand" "re,BM,0,le,re,BM")))
+	  (match_operand:SWI48 1 "nonimmediate_operand" "%0,0,r,r,rm,r,m,r")
+	  (match_operand:SWI48 2 "x86_64_general_operand" "re,BM,0,le,r,e,je,BM")))
    (clobber (reg:CC FLAGS_REG))]
   "ix86_binary_operator_ok (PLUS, <MODE>mode, operands,
 			    TARGET_APX_NDD)"
@@ -6457,7 +6457,7 @@
 		    : "add{<imodesuffix>}\t{%2, %0|%0, %2}";
     }
 }
-  [(set_attr "isa" "*,*,*,*,apx_ndd,apx_ndd")
+  [(set_attr "isa" "*,*,*,*,apx_ndd,apx_ndd,apx_ndd,apx_ndd")
    (set (attr "type")
      (cond [(eq_attr "alternative" "3")
               (const_string "lea")