From 2d163fa554136fe629c061144a5b22c5c293c9c0 Mon Sep 17 00:00:00 2001
From: Doyle Thai <dyl.thai@gmail.com>
Date: Sun, 2 Jul 2017 14:47:38 +1000
Subject: [PATCH] Add fix for strict-aliasing in DqnRnd

---
 build.bat         |  2 +-
 dqn.h             | 16 +++++++++++++---
 dqn_unit_test.cpp |  9 ++++-----
 makefile          |  2 +-
 4 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/build.bat b/build.bat
index 4b69675..fc3da94 100644
--- a/build.bat
+++ b/build.bat
@@ -31,7 +31,7 @@ REM Zi enables debug data, Z7 combines the debug files into one.
 REM W4 warning level 4
 REM WX treat warnings as errors
 REM wd4201 ignore: nonstandard extension used: nameless struct/union
-set CompileFlags=-EHsc -GR- -Oi -MT -Z7 -W4 -WX -wd4201 -FC -O2
+set CompileFlags=-EHsc -GR- -Oi -MT -Z7 -W4 -WX -wd4201 -FC -Od
 
 REM Include directories
 set IncludeFlags=
diff --git a/dqn.h b/dqn.h
index 4b9c681..4e39392 100644
--- a/dqn.h
+++ b/dqn.h
@@ -3951,13 +3951,22 @@ DQN_FILE_SCOPE i32 Dqn_I32ToWstr(i32 value, wchar_t *buf, i32 bufSize)
 
 // Convert a randomized u32 value to a float value x in the range 0.0f <= x
 // < 1.0f. Contributed by Jonatan Hedborg
+
+// NOTE: This is to abide to strict aliasing rules.
+union DqnRndInternal_U32F32
+{
+	u32 unsigned32;
+	f32 float32;
+};
+
 FILE_SCOPE f32 DqnRnd_F32NormalizedFromU32Internal(u32 value)
 {
 	u32 exponent = 127;
 	u32 mantissa = value >> 9;
-	u32 result   = (exponent << 23) | mantissa;
-	f32 fresult  = *(f32 *)(&result);
-	return fresult - 1.0f;
+
+	union DqnRndInternal_U32F32 uf;
+	uf.unsigned32 = (exponent << 23 | mantissa);
+	return uf.float32 - 1.0f;
 }
 
 FILE_SCOPE u64 DqnRnd_Murmur3Avalanche64Internal(u64 h)
@@ -4145,6 +4154,7 @@ PERFORMANCE vs MSVC 2008 32-/64-bit (GCC is even slower than MSVC):
 #ifdef __GNUC__
 	#pragma GCC diagnostic push
 	#pragma GCC diagnostic ignored "-Wmisleading-indentation"
+	#pragma GCC diagnostic ignored "-Wstrict-aliasing"
 #endif
 
 #include <stdlib.h>  // for va_arg()
diff --git a/dqn_unit_test.cpp b/dqn_unit_test.cpp
index 6032fc6..cfde316 100644
--- a/dqn_unit_test.cpp
+++ b/dqn_unit_test.cpp
@@ -343,7 +343,7 @@ void StringsTest()
 
 			char e[DQN_64BIT_NUM_MAX_STR_SIZE] = {};
 			Dqn_I64ToStr(SMALLEST_NUM, e, DQN_ARRAY_COUNT(e));
-			DQN_ASSERT(DqnStr_Cmp(e, "-9223372036854775808") == 0);
+			DQN_ASSERT_MSG(DqnStr_Cmp(e, "-9223372036854775808") == 0, "e: %s", e);
 
 			printf("StringsTest(): I64ToStr: Completed successfully\n");
 		}
@@ -569,18 +569,17 @@ void RandomTest()
 	PrintHeader("Random Number Generator Test");
 	DqnRandPCGState pcg;
 	DqnRnd_PCGInit(&pcg);
-	for (i32 i = 0; i < 10; i++)
+	for (i32 i = 0; i < 1000000; i++)
 	{
 		i32 min    = -100;
-		i32 max    = 100000;
+		i32 max    = 1000000000;
 		i32 result = DqnRnd_PCGRange(&pcg, min, max);
 		DQN_ASSERT(result >= min && result <= max);
 
 		f32 randF32 = DqnRnd_PCGNextf(&pcg);
 		DQN_ASSERT(randF32 >= 0.0f && randF32 <= 1.0f);
-		printf("RandomTest(): RndPCG: Completed successfully\n");
 	}
-
+	printf("RandomTest(): RndPCG: Completed successfully\n");
 	printf("RandomTest(): Completed successfully\n");
 }
 
diff --git a/makefile b/makefile
index 24d9329..33cd42a 100644
--- a/makefile
+++ b/makefile
@@ -1,3 +1,3 @@
 all: dqn_unit_test.cpp
 	mkdir -p bin
-	g++ -o bin/dqn_unit_test dqn_unit_test.cpp -lm -Wall -Werror -pthread -ggdb
+	g++ -o bin/dqn_unit_test dqn_unit_test.cpp -lm -Wall -Werror -pthread -ggdb -O3