From: liuhongt <hongtao.liu@intel.com>
Date: Fri, 19 Apr 2024 02:29:34 +0000 (+0800)
Subject: Simplify (AND (ASHIFTRT A imm) mask) to (LSHIFTRT A imm) for vector mode.
X-Git-Tag: basepoints/gcc-16~8506
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=r15-1047-g7876cde25cbd2f;p=thirdparty%2Fgcc.git

Simplify (AND (ASHIFTRT A imm) mask) to (LSHIFTRT A imm) for vector mode.

When mask is (1 << (prec - imm) - 1) which is used to clear upper bits
of A, then it can be simplified to LSHIFTRT.

i.e Simplify
(and:v8hi
  (ashifrt:v8hi A 8)
  (const_vector 0xff x8))
to
(lshifrt:v8hi A 8)

gcc/ChangeLog:

	PR target/114428
	* simplify-rtx.cc
	(simplify_context::simplify_binary_operation_1):
	Simplify (AND (ASHIFTRT A imm) mask) to (LSHIFTRT A imm) for
	specific mask.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr114428-1.c: New test.
---

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index f6b4d73b593..9bc3ef9ad9f 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -4065,6 +4065,31 @@ simplify_context::simplify_binary_operation_1 (rtx_code code,
 	    return tem;
 	}
 
+      /* (and:v4si
+	   (ashiftrt:v4si A 16)
+	   (const_vector: 0xffff x4))
+	 is just (lshiftrt:v4si A 16).  */
+      if (VECTOR_MODE_P (mode) && GET_CODE (op0) == ASHIFTRT
+	  && (CONST_INT_P (XEXP (op0, 1))
+	      || (GET_CODE (XEXP (op0, 1)) == CONST_VECTOR
+		  && CONST_VECTOR_DUPLICATE_P (XEXP (op0, 1))))
+	  && GET_CODE (op1) == CONST_VECTOR
+	  && CONST_VECTOR_DUPLICATE_P (op1))
+	{
+	  unsigned HOST_WIDE_INT shift_count
+	    = (CONST_INT_P (XEXP (op0, 1))
+	       ? UINTVAL (XEXP (op0, 1))
+	       : UINTVAL (XVECEXP (XEXP (op0, 1), 0, 0)));
+	  unsigned HOST_WIDE_INT inner_prec
+	    = GET_MODE_PRECISION (GET_MODE_INNER (mode));
+
+	  /* Avoid UD shift count.  */
+	  if (shift_count < inner_prec
+	      && (UINTVAL (XVECEXP (op1, 0, 0))
+		  == (HOST_WIDE_INT_1U << (inner_prec - shift_count)) - 1))
+	    return simplify_gen_binary (LSHIFTRT, mode, XEXP (op0, 0), XEXP (op0, 1));
+	}
+
       tem = simplify_byte_swapping_operation (code, mode, op0, op1);
       if (tem)
 	return tem;
diff --git a/gcc/testsuite/gcc.target/i386/pr114428-1.c b/gcc/testsuite/gcc.target/i386/pr114428-1.c
new file mode 100644
index 00000000000..927476f2269
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr114428-1.c
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse2" } */
+/* { dg-final { scan-assembler-times "psrlw" 1 } } */
+/* { dg-final { scan-assembler-times "psrld" 1 } } */
+/* { dg-final { scan-assembler-times "psrlq" 1 { target { ! ia32 } } } } */
+
+
+#define SHIFTC 12
+
+typedef int v4si __attribute__((vector_size(16)));
+typedef short v8hi __attribute__((vector_size(16)));
+typedef long long v2di __attribute__((vector_size(16)));
+
+v8hi
+foo1 (v8hi a)
+{
+  return
+    (a >> (16 - SHIFTC)) & (__extension__(v8hi){(1<<SHIFTC)-1, (1<<SHIFTC)-1,
+						(1<<SHIFTC)-1,(1<<SHIFTC)-1,
+						(1<<SHIFTC)-1, (1<<SHIFTC)-1,
+						(1<<SHIFTC)-1,(1<<SHIFTC)-1});
+}
+
+v4si
+foo2 (v4si a)
+{
+  return
+    (a >> (32 - SHIFTC)) & (__extension__(v4si){(1<<SHIFTC)-1, (1<<SHIFTC)-1,
+						(1<<SHIFTC)-1,(1<<SHIFTC)-1});
+}
+
+v2di
+__attribute__((target("avx512vl")))
+foo3 (v2di a)
+{
+  return
+    (a >> (long long)(64 - SHIFTC)) & (__extension__(v2di){(1ULL<<SHIFTC)-1,
+							   (1ULL<<SHIFTC)-1});
+}