s390: Fix TF to FPRX2 conversion [PR115860]

Currently subregs originating from *tf_to_fprx2_0 and *tf_to_fprx2_1
survive register allocation.  This in turn leads to wrong register
renaming.  Keeping the current approach would mean we need two insns for
*tf_to_fprx2_0 and *tf_to_fprx2_1, respectively.  Something along the
lines

(define_insn "*tf_to_fprx2_0"
  [(set (subreg:DF (match_operand:FPRX2 0 "nonimmediate_operand" "=f") 0)
        (unspec:DF [(match_operand:TF 1 "general_operand" "v")]
                   UNSPEC_TF_TO_FPRX2_0))]
  "TARGET_VXE"
  "#")

(define_insn "*tf_to_fprx2_0"
  [(set (match_operand:DF 0 "nonimmediate_operand" "=f")
        (unspec:DF [(match_operand:TF 1 "general_operand" "v")]
                   UNSPEC_TF_TO_FPRX2_0))]
  "TARGET_VXE"
  "vpdi\t%v0,%v1,%v0,1
  [(set_attr "op_type" "VRR")])

and similar for *tf_to_fprx2_1.  Note, pre register allocation operand 0
has mode FPRX2 and afterwards DF once subregs have been eliminated.

Since we always copy a whole vector register into a floating-point
register pair, another way to fix this is to merge *tf_to_fprx2_0 and
*tf_to_fprx2_1 into a single insn which means we don't have to use
subregs at all.  The downside of this is that the assembler template
contains two instructions, now.  The upside is that we don't have to
come up with some artificial insn before RA which might be more
readable/maintainable.  That is implemented by this patch.

In commit r11-4872-ge627cda5686592, the output operand specifier %V was
introduced which is used in tf_to_fprx2 only, now.  Instead of coming up
with its counterpart %F for floating-point registers, which would also
only be used in tf_to_fprx2, I print the operands directly.  This
renders %V unused which is why it is removed by this patch.

gcc/ChangeLog:

	PR target/115860
	* config/s390/s390.cc (print_operand): Remove operand specifier
	%V.
	* config/s390/s390.md (UNSPEC_TF_TO_FPRX2): New.
	* config/s390/vector.md (*tf_to_fprx2_0): Remove.
	(*tf_to_fprx2_1): Remove.
	(tf_to_fprx2): New.

gcc/testsuite/ChangeLog:

	* gcc.target/s390/vector/long-double-asm-abi.c: Adapt
	scan-assembler directive.
	* gcc.target/s390/vector/long-double-to-i64.c: Adapt
	scan-assembler directive.
	* gcc.target/s390/pr115860-1.c: New test.

(cherry picked from commit 46c2538435dfc50dd5c67c4e03ce387d1f6ebe9b)

diff --git a/gcc/config/s390/s390.cc b/gcc/config/s390/s390.cc
index 2be3a873b891aed5e16ad7a6aaed7f16566d8952..a8f804ffe4f78a73c1268a5ca8b8c60f82662dc1 100644 (file)
--- a/gcc/config/s390/s390.cc
+++ b/gcc/config/s390/s390.cc
@@ -8028,7 +8028,6 @@ print_operand_address (FILE *file, rtx addr)
         CONST_VECTOR: Generate a bitmask for vgbm instruction.
     'x': print integer X as if it's an unsigned halfword.
     'v': print register number as vector register (v1 instead of f1).
-    'V': print the second word of a TFmode operand as vector register.
 */
 
 void
@@ -8221,13 +8220,13 @@ print_operand (FILE *file, rtx x, int code)
     case REG:
       /* Print FP regs as fx instead of vx when they are accessed
         through non-vector mode.  */
-      if ((code == 'v' || code == 'V')
+      if (code == 'v'
          || VECTOR_NOFP_REG_P (x)
          || (FP_REG_P (x) && VECTOR_MODE_P (GET_MODE (x)))
          || (VECTOR_REG_P (x)
              && (GET_MODE_SIZE (GET_MODE (x)) /
                  s390_class_max_nregs (FP_REGS, GET_MODE (x))) > 8))
-       fprintf (file, "%%v%s", reg_names[REGNO (x) + (code == 'V')] + 2);
+       fprintf (file, "%%v%s", reg_names[REGNO (x)] + 2);
       else
        fprintf (file, "%s", reg_names[REGNO (x)]);
       break;

diff --git a/gcc/config/s390/s390.md b/gcc/config/s390/s390.md
index 2fc799695377ffda95070712cd99e363a9896341..335aff9884e2085268965fa60e15c9f26b8ab46b 100644 (file)
--- a/gcc/config/s390/s390.md
+++ b/gcc/config/s390/s390.md
@@ -244,6 +244,8 @@
 
    UNSPEC_VEC_ELTSWAP
 
+   UNSPEC_TF_TO_FPRX2
+
    UNSPEC_NNPA_VCLFNHS_V8HI
    UNSPEC_NNPA_VCLFNLS_V8HI
    UNSPEC_NNPA_VCRNFS_V8HI

diff --git a/gcc/config/s390/vector.md b/gcc/config/s390/vector.md
index 75912280c23dd3f1cc3b17097a92581b182fcbd6..ac3816a6f5c663986051d589903a6142c3a2bc3f 100644 (file)
--- a/gcc/config/s390/vector.md
+++ b/gcc/config/s390/vector.md
@@ -900,36 +900,45 @@
   "vmrlg\t%0,%1,%2";
   [(set_attr "op_type" "VRR")])
 
-
-(define_insn "*tf_to_fprx2_0"
-  [(set (subreg:DF (match_operand:FPRX2 0 "nonimmediate_operand" "+f") 0)
-       (subreg:DF (match_operand:TF    1 "general_operand"       "v") 0))]
-  "TARGET_VXE"
-  ; M4 == 1 corresponds to %v0[0] = %v1[0]; %v0[1] = %v0[1];
-  "vpdi\t%v0,%v1,%v0,1"
-  [(set_attr "op_type" "VRR")])
-
-(define_insn "*tf_to_fprx2_1"
-  [(set (subreg:DF (match_operand:FPRX2 0 "nonimmediate_operand" "+f") 8)
-       (subreg:DF (match_operand:TF    1 "general_operand"       "v") 8))]
+(define_insn "tf_to_fprx2"
+  [(set (match_operand:FPRX2             0 "register_operand" "=f,f ,f")
+       (unspec:FPRX2 [(match_operand:TF 1 "general_operand"   "v,AR,AT")]
+                     UNSPEC_TF_TO_FPRX2))]
   "TARGET_VXE"
-  ; M4 == 5 corresponds to %V0[0] = %v1[1]; %V0[1] = %V0[1];
-  "vpdi\t%V0,%v1,%V0,5"
-  [(set_attr "op_type" "VRR")])
-
-(define_insn_and_split "tf_to_fprx2"
-  [(set (match_operand:FPRX2            0 "nonimmediate_operand" "=f,f")
-       (subreg:FPRX2 (match_operand:TF 1 "general_operand"       "v,AR") 0))]
-  "TARGET_VXE"
-  "#"
-  "!(MEM_P (operands[1]) && MEM_VOLATILE_P (operands[1]))"
-  [(set (match_dup 2) (match_dup 3))
-   (set (match_dup 4) (match_dup 5))]
 {
-  operands[2] = simplify_gen_subreg (DFmode, operands[0], FPRX2mode, 0);
-  operands[3] = simplify_gen_subreg (DFmode, operands[1], TFmode, 0);
-  operands[4] = simplify_gen_subreg (DFmode, operands[0], FPRX2mode, 8);
-  operands[5] = simplify_gen_subreg (DFmode, operands[1], TFmode, 8);
+  char buf[64];
+  const char *reg_pair = reg_names[REGNO (operands[0]) + 1];
+  switch (which_alternative)
+    {
+    case 0:
+      if (REGNO (operands[0]) == REGNO (operands[1]))
+       {
+         reg_pair += 2;  // get rid of prefix %f
+         snprintf (buf, sizeof (buf), "vpdi\t%%%%v%s,%%v1,%%%%v%s,5", reg_pair, reg_pair);
+         output_asm_insn (buf, operands);
+         return "";
+       }
+      else
+       {
+         reg_pair += 2;  // get rid of prefix %f
+         snprintf (buf, sizeof (buf), "ldr\t%%f0,%%f1;vpdi\t%%%%v%s,%%v1,%%%%v%s,5", reg_pair, reg_pair);
+         output_asm_insn (buf, operands);
+         return "";
+       }
+    case 1:
+      {
+       snprintf (buf, sizeof (buf), "ld\t%%f0,%%1;ld\t%%%s,8+%%1", reg_pair);
+       output_asm_insn (buf, operands);
+       return "";
+      }
+    case 2:
+      {
+       snprintf (buf, sizeof (buf), "ldy\t%%f0,%%1;ldy\t%%%s,8+%%1", reg_pair);
+       output_asm_insn (buf, operands);
+       return "";
+      }
+    default: gcc_unreachable ();
+    }
 })
 
 
@@ -2548,9 +2557,8 @@
 ; There is no instruction for rounding an extended BFP operand in a VR into
 ; a signed integer, therefore copy it into a FPR pair first.
 (define_expand "fix_trunctf<mode>2_vr"
-  [(set (subreg:DF (match_dup 2) 0)
-       (subreg:DF (match_operand:TF 1 "register_operand" "") 0))
-   (set (subreg:DF (match_dup 2) 8) (subreg:DF (match_dup 1) 8))
+  [(set (match_dup 2)
+       (unspec:FPRX2 [(match_operand:TF 1 "register_operand")] UNSPEC_TF_TO_FPRX2))
    (parallel [(set (match_operand:GPR 0 "register_operand" "")
                   (fix:GPR (match_dup 2)))
              (unspec:GPR [(const_int BFP_RND_TOWARD_0)] UNSPEC_ROUND)
@@ -2582,9 +2590,8 @@
 ; There is no instruction for rounding an extended BFP operand in a VR into
 ; an unsigned integer, therefore copy it into a FPR pair first.
 (define_expand "fixuns_trunctf<mode>2_vr"
-  [(set (subreg:DF (match_dup 2) 0)
-       (subreg:DF (match_operand:TF 1 "register_operand" "") 0))
-   (set (subreg:DF (match_dup 2) 8) (subreg:DF (match_dup 1) 8))
+  [(set (match_dup 2)
+       (unspec:FPRX2 [(match_operand:TF 1 "register_operand")] UNSPEC_TF_TO_FPRX2))
    (parallel [(set (match_operand:GPR 0 "register_operand" "")
                   (unsigned_fix:GPR (match_dup 2)))
              (unspec:GPR [(const_int BFP_RND_TOWARD_0)] UNSPEC_ROUND)

diff --git a/gcc/testsuite/gcc.target/s390/pr115860-1.c b/gcc/testsuite/gcc.target/s390/pr115860-1.c
new file mode 100644 (file)
index 0000000..abcddea
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/pr115860-1.c
@@ -0,0 +1,26 @@
+/* { dg-do run } */
+/* { dg-require-effective-target s390_vxe } */
+/* { dg-options "-O2 -march=z14 -mzarch" } */
+
+__attribute__ ((noipa))
+long long trunctf (long double x)
+{
+  /* Ensure via ++x that x is in a register.  */
+  ++x;
+  return x;
+}
+
+__attribute__ ((noipa))
+long long trunctf_from_mem (long double x)
+{
+  return x;
+}
+
+int main (void)
+{
+  if (trunctf (0x7ffffffffffffffeLL) != 0x7fffffffffffffffLL)
+    __builtin_abort ();
+  if (trunctf_from_mem (0x7fffffffffffffffLL) != 0x7fffffffffffffffLL)
+    __builtin_abort ();
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.target/s390/vector/long-double-asm-abi.c b/gcc/testsuite/gcc.target/s390/vector/long-double-asm-abi.c
index f9f2d1286e2da7bfd3f2e9a490f75aa39d953e27..ac3576801f09215c3d2ca377c27c9f03ba458897 100644 (file)
--- a/gcc/testsuite/gcc.target/s390/vector/long-double-asm-abi.c
+++ b/gcc/testsuite/gcc.target/s390/vector/long-double-asm-abi.c
@@ -14,7 +14,7 @@ xsqrt (long double x)
 
 /* Check that the generated code is very small and straightforward.  In
    particular, there must be no unnecessary copying and no stack frame.  */
-/* { dg-final { scan-assembler {\n\tld\t[^\n]*\n\tld\t[^\n]*\n(#[^\n]*\n)*\tsqxbr\t.*\n(#[^\n]*\n)*\tstd\t[^\n]*\n\tstd\t[^\n]*\n\tbr\t%r14\n} } } */
+/* { dg-final { scan-assembler {\n\tld\t[^\n]*;ld\t[^\n]*\n(#[^\n]*\n)*\tsqxbr\t.*\n(#[^\n]*\n)*\tstd\t[^\n]*\n\tstd\t[^\n]*\n\tbr\t%r14\n} } } */
 
 int
 main (void)

diff --git a/gcc/testsuite/gcc.target/s390/vector/long-double-to-i64.c b/gcc/testsuite/gcc.target/s390/vector/long-double-to-i64.c
index 2dbbb5d1c03e7a56c1a740a87bf6d33d09313e83..ed47fd9b85898f8ae1ad1c5b26b4a170846ff96e 100644 (file)
--- a/gcc/testsuite/gcc.target/s390/vector/long-double-to-i64.c
+++ b/gcc/testsuite/gcc.target/s390/vector/long-double-to-i64.c
@@ -10,8 +10,6 @@ long_double_to_i64 (long double x)
   return x;
 }
 
-/* { dg-final { scan-assembler-times {\n\tvpdi\t%v\d+,%v\d+,%v\d+,1\n} 1 } } */
-/* { dg-final { scan-assembler-times {\n\tvpdi\t%v\d+,%v\d+,%v\d+,5\n} 1 } } */
 /* { dg-final { scan-assembler-times {\n\tcgxbr\t} 1 } } */
 
 int