[gcc r12-6433] rs6000: powerpc suboptimal boolean test of contiguous bits [PR102239]

[Xiong Hu Luo]

https://gcc.gnu.org/g:19d81fda48f30c4fc11c8912749351acd9159c17

commit r12-6433-g19d81fda48f30c4fc11c8912749351acd9159c17
Author: Xionghu Luo <luoxhu@linux.ibm.com>
Date:   Sun Dec 12 23:17:13 2021 -0600

    rs6000: powerpc suboptimal boolean test of contiguous bits [PR102239]
    
    Add specialized version to combine two instructions from
    
     9: {r123:CC=cmp(r124:DI&0x600000000,0);clobber scratch;}
           REG_DEAD r124:DI
     10: pc={(r123:CC==0)?L15:pc}
          REG_DEAD r123:CC
    
    to:
    
     10: {pc={(r123:DI&0x600000000==0)?L15:pc};clobber scratch;clobber %0:CC;}
    
    then split2 will split it to one rotate dot instruction (to save one
    rotate back instruction) as shifted result doesn't matter when comparing
    to 0 in CCEQmode.
    
    Bootstrapped and regression tested pass on Power 8/9/10.
    
    gcc/ChangeLog:
    
            PR target/102239
            * config/rs6000/rs6000-protos.h (rs6000_is_valid_rotate_dot_mask): New
            declare.
            * config/rs6000/rs6000.c (rs6000_is_valid_rotate_dot_mask): New
            function.
            * config/rs6000/rs6000.md (*branch_anddi3_dot): New.
    
    gcc/testsuite/ChangeLog:
    
            PR target/102239
            * gcc.target/powerpc/pr102239.c: New test.

Diff:
---
 gcc/config/rs6000/rs6000-protos.h           |  1 +
 gcc/config/rs6000/rs6000.c                  |  7 ++++++
 gcc/config/rs6000/rs6000.md                 | 38 +++++++++++++++++++++++++++++
 gcc/testsuite/gcc.target/powerpc/pr102239.c | 13 ++++++++++
 4 files changed, 59 insertions(+)

diff --git a/gcc/config/rs6000/rs6000-protos.h b/gcc/config/rs6000/rs6000-protos.h
index 55e082e7d92..1d1c89cd406 100644
--- a/gcc/config/rs6000/rs6000-protos.h
+++ b/gcc/config/rs6000/rs6000-protos.h
@@ -73,6 +73,7 @@ extern int expand_block_move (rtx[], bool);
 extern bool expand_block_compare (rtx[]);
 extern bool expand_strn_compare (rtx[], int);
 extern bool rs6000_is_valid_mask (rtx, int *, int *, machine_mode);
+extern bool rs6000_is_valid_rotate_dot_mask (rtx mask, machine_mode mode);
 extern bool rs6000_is_valid_and_mask (rtx, machine_mode);
 extern bool rs6000_is_valid_shift_mask (rtx, rtx, machine_mode);
 extern bool rs6000_is_valid_insert_mask (rtx, rtx, machine_mode);
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index f4c7d836f40..e7b5b2c5a7d 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -11394,6 +11394,13 @@ rs6000_is_valid_mask (rtx mask, int *b, int *e, machine_mode mode)
   return true;
 }
 
+bool
+rs6000_is_valid_rotate_dot_mask (rtx mask, machine_mode mode)
+{
+  int nb, ne;
+  return rs6000_is_valid_mask (mask, &nb, &ne, mode) && nb >= ne && ne > 0;
+}
+
 /* Return whether MASK (a CONST_INT) is a valid mask for any rlwinm, rldicl,
    or rldicr instruction, to implement an AND with it in mode MODE.  */
 
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 6ecb0bd6142..6f74075f58d 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -3767,6 +3767,44 @@
    (set_attr "dot" "yes")
    (set_attr "length" "8,12")])
 
+(define_insn_and_split "*branch_anddi3_dot"
+ [(set (pc)
+    (if_then_else (eq (and:DI (match_operand:DI 1 "gpc_reg_operand" "%r,r")
+			      (match_operand:DI 2 "const_int_operand" "n,n"))
+		      (const_int 0))
+		  (label_ref (match_operand 3 ""))
+		  (pc)))
+  (clobber (match_scratch:DI 0 "=r,r"))
+  (clobber (reg:CC CR0_REGNO))]
+  "rs6000_is_valid_rotate_dot_mask (operands[2], DImode)
+  && TARGET_POWERPC64"
+  "#"
+  "&& reload_completed"
+  [(pc)]
+{
+   int nb, ne;
+   if (rs6000_is_valid_mask (operands[2], &nb, &ne, DImode)
+       && nb >= ne
+       && ne > 0)
+     {
+	unsigned HOST_WIDE_INT val = INTVAL (operands[2]);
+	int shift = 63 - nb;
+	rtx tmp = gen_rtx_ASHIFT (DImode, operands[1], GEN_INT (shift));
+	tmp = gen_rtx_AND (DImode, tmp, GEN_INT (val << shift));
+	rtx cr0 = gen_rtx_REG (CCmode, CR0_REGNO);
+	rs6000_emit_dot_insn (operands[0], tmp, 1, cr0);
+	rtx loc_ref = gen_rtx_LABEL_REF (VOIDmode, operands[3]);
+	rtx cond = gen_rtx_EQ (CCEQmode, cr0, const0_rtx);
+	rtx ite = gen_rtx_IF_THEN_ELSE (VOIDmode, cond, loc_ref, pc_rtx);
+	emit_jump_insn (gen_rtx_SET (pc_rtx, ite));
+	DONE;
+     }
+   else
+     FAIL;
+}
+  [(set_attr "type" "shift")
+   (set_attr "dot" "yes")
+   (set_attr "length" "8,12")])
 
 (define_expand "<code><mode>3"
   [(set (match_operand:SDI 0 "gpc_reg_operand")
diff --git a/gcc/testsuite/gcc.target/powerpc/pr102239.c b/gcc/testsuite/gcc.target/powerpc/pr102239.c
new file mode 100644
index 00000000000..2ff72b7deca
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr102239.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-O2" } */
+
+void foo(long arg)
+{
+  if (arg & ((1UL << 33) | (1UL << 34)))
+    asm volatile("# if");
+  else
+    asm volatile("# else");
+}
+
+/* { dg-final { scan-assembler-times {\mrldicr\.} 1 } } */