[gcc/devel/omp/gcc-9] aarch64: Fix aarch64_expand_subvti constant handling [PR93335]

[Tobias Burnus]

https://gcc.gnu.org/g:b6c79134021b328e8ab379d4d8c76f4e3c061b44

commit b6c79134021b328e8ab379d4d8c76f4e3c061b44
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Jan 22 18:08:31 2020 +0100

    aarch64: Fix aarch64_expand_subvti constant handling [PR93335]
    
    The two patterns that call aarch64_expand_subvti ensure that {low,high}_in1
    is a register, while {low,high}_in2 can be a register or immediate.
    subdi3_compare1_imm uses the aarch64_plus_immediate predicate for its last
    two operands (the value and negated value), but aarch64_expand_subvti calls
    it whenever low_in2 is a CONST_INT, which leads to ICEs during vregs pass,
    as the emitted insn is not recognized as valid subdi3_compare1_imm.
    The following patch fixes that by only using subdi3_compare1_imm if it is ok
    to do so, and otherwise force the constant into register and use the
    non-immediate version - subdi3_compare1.
    Furthermore, previously the code was calling force_reg on high_in2 only if
    low_in2 is CONST_INT, on the (reasonable) assumption is that only if low_in2
    is a CONST_INT, high_in2 can be non-REG, but with the above changes even in
    the else we might have CONST_INT and force_reg doesn't do anything if the
    operand is already a REG, so this patch calls it unconditionally.
    
    2020-01-22  Jakub Jelinek  <jakub@redhat.com>
    
    	PR target/93335
    	* config/aarch64/aarch64.c (aarch64_expand_subvti): Only use
    	gen_subdi3_compare1_imm if low_in2 satisfies aarch64_plus_immediate
    	predicate, not whenever it is CONST_INT.  Otherwise, force_reg it.
    	Call force_reg on high_in2 unconditionally.
    
    	* gcc.c-torture/compile/pr93335.c: New test.

Diff:
---
 gcc/ChangeLog                                 |  8 +++
 gcc/config/aarch64/aarch64.c                  | 13 ++--
 gcc/testsuite/ChangeLog                       |  5 ++
 gcc/testsuite/gcc.c-torture/compile/pr93335.c | 98 +++++++++++++++++++++++++++
 4 files changed, 118 insertions(+), 6 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1d62d16..b91e5ca 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2020-01-22  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/93335
+	* config/aarch64/aarch64.c (aarch64_expand_subvti): Only use
+	gen_subdi3_compare1_imm if low_in2 satisfies aarch64_plus_immediate
+	predicate, not whenever it is CONST_INT.  Otherwise, force_reg it.
+	Call force_reg on high_in2 unconditionally.
+
+2020-01-22  Jakub Jelinek  <jakub@redhat.com>
+
 	PR target/91298
 	* output.h (assemble_name_resolve): Declare.
 	* varasm.c (assemble_name_resolve): New function.
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 82e9b1f..90c6ea3 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -17247,14 +17247,15 @@ aarch64_expand_subvti (rtx op0, rtx low_dest, rtx low_in1,
     }
   else
     {
-      if (CONST_INT_P (low_in2))
+      if (aarch64_plus_immediate (low_in2, DImode))
+	emit_insn (gen_subdi3_compare1_imm (low_dest, low_in1, low_in2,
+					    GEN_INT (-INTVAL (low_in2))));
+      else
 	{
-	  high_in2 = force_reg (DImode, high_in2);
-	  emit_insn (gen_subdi3_compare1_imm (low_dest, low_in1, low_in2,
-					      GEN_INT (-INTVAL (low_in2))));
+	  low_in2 = force_reg (DImode, low_in2);
+	  emit_insn (gen_subdi3_compare1 (low_dest, low_in1, low_in2));
 	}
-      else
-	emit_insn (gen_subdi3_compare1 (low_dest, low_in1, low_in2));
+      high_in2 = force_reg (DImode, high_in2);
 
       if (unsigned_p)
 	emit_insn (gen_usubdi3_carryinC (high_dest, high_in1, high_in2));
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bebe9a7..60c0a8a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2020-01-22  Jakub Jelinek  <jakub@redhat.com>
 
+	PR target/93335
+	* gcc.c-torture/compile/pr93335.c: New test.
+
+2020-01-22  Jakub Jelinek  <jakub@redhat.com>
+
 	PR target/91298
 	* gcc.target/i386/pr91298-1.c: New test.
 	* gcc.target/i386/pr91298-2.c: New test.
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr93335.c b/gcc/testsuite/gcc.c-torture/compile/pr93335.c
new file mode 100644
index 0000000..c6e984c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr93335.c
@@ -0,0 +1,98 @@
+/* PR target/93335 */
+/* { dg-do compile { target int128 } } */
+
+int
+f1 (unsigned int x)
+{
+  return __builtin_sub_overflow_p (x, 4096, (unsigned __int128) 0);
+}
+
+int
+f2 (unsigned int x)
+{
+  return __builtin_sub_overflow_p (x, 4097, (unsigned __int128) 0);
+}
+
+int
+f3 (int x)
+{
+  return __builtin_sub_overflow_p (x, 4096, (__int128) 0);
+}
+
+int
+f4 (int x)
+{
+  return __builtin_sub_overflow_p (x, 4097, (__int128) 0);
+}
+
+int
+f5 (unsigned int x)
+{
+  return __builtin_sub_overflow_p (x, -4096, (unsigned __int128) 0);
+}
+
+int
+f6 (unsigned int x)
+{
+  return __builtin_sub_overflow_p (x, -4097, (unsigned __int128) 0);
+}
+
+int
+f7 (int x)
+{
+  return __builtin_sub_overflow_p (x, -4096, (__int128) 0);
+}
+
+int
+f8 (int x)
+{
+  return __builtin_sub_overflow_p (x, -4097, (__int128) 0);
+}
+
+int
+f9 (unsigned int x)
+{
+  return __builtin_add_overflow_p (x, 4096, (unsigned __int128) 0);
+}
+
+int
+f10 (unsigned int x)
+{
+  return __builtin_add_overflow_p (x, 4097, (unsigned __int128) 0);
+}
+
+int
+f11 (int x)
+{
+  return __builtin_add_overflow_p (x, 4096, (__int128) 0);
+}
+
+int
+f12 (int x)
+{
+  return __builtin_add_overflow_p (x, 4097, (__int128) 0);
+}
+
+int
+f13 (unsigned int x)
+{
+  return __builtin_add_overflow_p (x, -4096, (unsigned __int128) 0);
+}
+
+int
+f14 (unsigned int x)
+{
+  return __builtin_add_overflow_p (x, -4097, (unsigned __int128) 0);
+}
+
+int
+f15 (int x)
+{
+  return __builtin_add_overflow_p (x, -4096, (__int128) 0);
+}
+
+int
+f16 (int x)
+{
+  return __builtin_add_overflow_p (x, -4097, (__int128) 0);
+}