From 081bcaddc552b649bee9ebea14b6c73448f58a3a Mon Sep 17 00:00:00 2001
From: Andrew Waterman <andrew@sifive.com>
Date: Wed, 18 Nov 2020 16:05:43 -0800
Subject: [PATCH] Avoid use of __builtin_popcount for portability

---
 riscv/arith.h         | 11 +++++++++++
 riscv/insns/bdep.h    |  2 +-
 riscv/insns/bdepw.h   |  2 +-
 riscv/insns/bext.h    |  2 +-
 riscv/insns/bextw.h   |  2 +-
 riscv/insns/bmatxor.h |  2 +-
 6 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/riscv/arith.h b/riscv/arith.h
index c9d39796..72bb5157 100644
--- a/riscv/arith.h
+++ b/riscv/arith.h
@@ -121,6 +121,17 @@ static inline uint64_t make_mask64(int pos, int len)
     return (UINT64_MAX >> (64 - len)) << pos;
 }
 
+static inline int popcount(uint64_t val)
+{
+  val = (val & 0x5555555555555555U) + ((val >>  1) & 0x5555555555555555U);
+  val = (val & 0x3333333333333333U) + ((val >>  2) & 0x3333333333333333U);
+  val = (val & 0x0f0f0f0f0f0f0f0fU) + ((val >>  4) & 0x0f0f0f0f0f0f0f0fU);
+  val = (val & 0x00ff00ff00ff00ffU) + ((val >>  8) & 0x00ff00ff00ff00ffU);
+  val = (val & 0x0000ffff0000ffffU) + ((val >> 16) & 0x0000ffff0000ffffU);
+  val = (val & 0x00000000ffffffffU) + ((val >> 32) & 0x00000000ffffffffU);
+  return val;
+}
+
 static inline int ctz(uint64_t val)
 {
   if (!val)
diff --git a/riscv/insns/bdep.h b/riscv/insns/bdep.h
index 92e28543..e71976f4 100644
--- a/riscv/insns/bdep.h
+++ b/riscv/insns/bdep.h
@@ -3,7 +3,7 @@ uint64_t c = 0, i = 0, data = zext_xlen(RS1), mask = zext_xlen(RS2);
 while (mask) {
 	uint64_t b = mask & ~((mask | (mask-1)) + 1);
 	c |= (data << (ctz(b) - i)) & b;
-	i += __builtin_popcountl(b);
+	i += popcount(b);
 	mask -= b;
 }
 WRITE_RD(sext_xlen(c));
diff --git a/riscv/insns/bdepw.h b/riscv/insns/bdepw.h
index 882dbdde..1c06251a 100644
--- a/riscv/insns/bdepw.h
+++ b/riscv/insns/bdepw.h
@@ -4,7 +4,7 @@ uint64_t c = 0, i = 0, data = zext32(RS1), mask = zext32(RS2);
 while (mask) {
 	uint64_t b = mask & ~((mask | (mask-1)) + 1);
 	c |= (data << (ctz(b) - i)) & b;
-	i += __builtin_popcountl(b);
+	i += popcount(b);
 	mask -= b;
 }
 WRITE_RD(sext32(c));
diff --git a/riscv/insns/bext.h b/riscv/insns/bext.h
index a03ea6f6..b0ed4a87 100644
--- a/riscv/insns/bext.h
+++ b/riscv/insns/bext.h
@@ -3,7 +3,7 @@ uint64_t c = 0, i = 0, data = zext_xlen(RS1), mask = zext_xlen(RS2);
 while (mask) {
 	uint64_t b = mask & ~((mask | (mask-1)) + 1);
 	c |= (data & b) >> (ctz(b) - i);
-	i += __builtin_popcountl(b);
+	i += popcount(b);
 	mask -= b;
 }
 WRITE_RD(sext_xlen(c));
diff --git a/riscv/insns/bextw.h b/riscv/insns/bextw.h
index 5e6ee47b..68377142 100644
--- a/riscv/insns/bextw.h
+++ b/riscv/insns/bextw.h
@@ -4,7 +4,7 @@ uint64_t c = 0, i = 0, data = zext32(RS1), mask = zext32(RS2);
 while (mask) {
 	uint64_t b = mask & ~((mask | (mask-1)) + 1);
 	c |= (data & b) >> (ctz(b) - i);
-	i += __builtin_popcountl(b);
+	i += popcount(b);
 	mask -= b;
 }
 WRITE_RD(sext32(c));
diff --git a/riscv/insns/bmatxor.h b/riscv/insns/bmatxor.h
index 06d9db0a..e4dedfdb 100644
--- a/riscv/insns/bmatxor.h
+++ b/riscv/insns/bmatxor.h
@@ -22,7 +22,7 @@ for (int i = 0; i < 8; i++) {
 
 uint64_t x = 0;
 for (int i = 0; i < 64; i++) {
-  if (__builtin_popcountl(u[i / 8] & v[i % 8]) & 1)
+  if (popcount(u[i / 8] & v[i % 8]) & 1)
     x |= 1LL << i;
 }