On Tue, Aug 2, 2022 at 11:53 PM Nathan Bossart
wrote:
> I did a bit of cross-checking, and AFAICT this is a reasonable starting
> point. emmintrin.h appears to be sufficient for one of my patches that
> makes use of SSE2 instructions. That being said, I imagine it'll be
> especially important to keep an eye on the buildfarm when this change is
> committed.
Thanks for checking! Here's a concrete patch for testing.
--
John Naylor
EDB: http://www.enterprisedb.com
From 0e01cc8f5f1c2c27631953091a1d657c5e5486be Mon Sep 17 00:00:00 2001
From: John Naylor
Date: Wed, 3 Aug 2022 11:07:40 +0700
Subject: [PATCH v1] Support SSE2 intrinsics where available
SSE2 vector instructions are part of the spec for the 64-bit x86
architecture. Until now we have relied on the compiler to autovectorize
in some limited situations, but some useful coding idioms can only be
expressed explicitly via compiler intrinsics. To this end, add a header
that defines USE_SSE2 when available. While x86-only for now, we can
add other architectures in the future. This will also be the intended
place for low-level hepler functions that use vector operations.
Reviewed by Nathan Bossart
Discussion: https://www.postgresql.org/message-id/CAFBsxsE2G_H_5Wbw%2BNOPm70-BK4xxKf86-mRzY%3DL2sLoQqM%2B-Q%40mail.gmail.com
---
src/include/port/simd.h | 30 ++
1 file changed, 30 insertions(+)
create mode 100644 src/include/port/simd.h
diff --git a/src/include/port/simd.h b/src/include/port/simd.h
new file mode 100644
index 00..a571e79f57
--- /dev/null
+++ b/src/include/port/simd.h
@@ -0,0 +1,30 @@
+/*-
+ *
+ * simd.h
+ * Support for platform-specific vector operations.
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/port/simd.h
+ *
+ *-
+ */
+#ifndef SIMD_H
+#define SIMD_H
+
+/*
+ * SSE2 instructions are part of the spec for the 64-bit x86 ISA. We assume
+ * that compilers targeting this architecture understand SSE2 intrinsics.
+ *
+ * We use emmintrin.h rather than the comprehensive header immintrin.h in
+ * order to exclude extensions beyond SSE2. This is because MSVC, at least,
+ * will allow the use of intrinsics that haven't been enabled at compile
+ * time.
+ */
+#if (defined(__x86_64__) || defined(_M_AMD64))
+#include
+#define USE_SSE2
+#endif
+
+#endif /* SIMD_H */
--
2.36.1
