Fix binary matching on floating point middle-endian machines

This complements 933e701 (OTP-10209). Without this patch the test case
"bs_match_misc_SUITE:t_float/1" fails.

Simple error example:
1> <<_,_,_,_,_,_,_,_>> = <<1.25/float>>.
<<63,244,0,0,0,0,0,0>>
2> <<1.25/float>> = <<63,244,0,0,0,0,0,0>>.
** exception error: no match of right hand side value <<63,244,0,0,0,0,0,0>>

The additional test case is added because in a former version of this
patch the ERTS_FP_ERROR_THOROUGH check for NaN/infinity was mistakenly
applied on the still word-switched double.

3 files changed, 27 insertions, 4 deletions

diff --git a/erts/emulator/beam/erl_bits.c b/erts/emulator/beam/erl_bits.c
index 3753b618e1..06d53efb5e 100644
--- a/erts/emulator/beam/erl_bits.c
+++ b/erts/emulator/beam/erl_bits.c
@@ -484,8 +484,16 @@ erts_bs_get_float_2(Process *p, Uint num_bits, unsigned flags, ErlBinMatchBuffer
 	ERTS_FP_ERROR_THOROUGH(p, f32, return THE_NON_VALUE);
 	f.fd = f32;
     } else {
+#ifdef DOUBLE_MIDDLE_ENDIAN
+	FloatDef ftmp;
+	ftmp.fd = f64;
+	f.fw[0] = ftmp.fw[1];
+	f.fw[1] = ftmp.fw[0];
+	ERTS_FP_ERROR_THOROUGH(p, f.fd, return THE_NON_VALUE);
+#else
 	ERTS_FP_ERROR_THOROUGH(p, f64, return THE_NON_VALUE);
 	f.fd = f64;
+#endif
     }
     mb->offset += num_bits;
     hp = HeapOnlyAlloc(p, FLOAT_SIZE_OBJECT);
diff --git a/erts/emulator/test/bs_match_misc_SUITE.erl b/erts/emulator/test/bs_match_misc_SUITE.erl
index 15427661f3..b0904acbe9 100644
--- a/erts/emulator/test/bs_match_misc_SUITE.erl
+++ b/erts/emulator/test/bs_match_misc_SUITE.erl
@@ -23,7 +23,8 @@
 	 bound_var/1,bound_tail/1,t_float/1,little_float/1,sean/1,
 	 kenneth/1,encode_binary/1,native/1,happi/1,
 	 size_var/1,wiger/1,x0_context/1,huge_float_field/1,
-	 writable_binary_matched/1,otp_7198/1,unordered_bindings/1]).
+	 writable_binary_matched/1,otp_7198/1,unordered_bindings/1,
+	 float_middle_endian/1]).
 
 -include_lib("test_server/include/test_server.hrl").
 
@@ -33,7 +34,7 @@ all() ->
     [bound_var, bound_tail, t_float, little_float, sean,
      kenneth, encode_binary, native, happi, size_var, wiger,
      x0_context, huge_float_field, writable_binary_matched,
-     otp_7198, unordered_bindings].
+     otp_7198, unordered_bindings, float_middle_endian].
 
 groups() -> 
     [].
@@ -92,6 +93,13 @@ t_float(Config) when is_list(Config) ->
 
     ok.
 
+float_middle_endian(Config) when is_list(Config) ->
+    F = 9007199254740990.0, % turns to -NaN when word-swapped
+    ?line fcmp(F, match_float(<<F:64/float>>, 64, 0)),
+    ?line fcmp(F, match_float(<<1:1,F:64/float,127:7>>, 64, 1)),
+    ?line fcmp(F, match_float(<<1:13,F:64/float,127:3>>, 64, 13)),
+    ok.
+
 
 fcmp(F1, F2) when (F1 - F2) / F2 < 0.0000001 -> ok.
     
diff --git a/lib/debugger/test/bs_match_misc_SUITE.erl b/lib/debugger/test/bs_match_misc_SUITE.erl
index 6b66c45448..54fa9a59df 100644
--- a/lib/debugger/test/bs_match_misc_SUITE.erl
+++ b/lib/debugger/test/bs_match_misc_SUITE.erl
@@ -26,7 +26,7 @@
 	 kenneth/1,encode_binary/1,native/1,happi/1,
 	 size_var/1,wiger/1,x0_context/1,huge_float_field/1,
 	 writable_binary_matched/1,otp_7198/1,
-	 unordered_bindings/1]).
+	 unordered_bindings/1,float_middle_endian/1]).
 
 -include_lib("test_server/include/test_server.hrl").
 
@@ -36,7 +36,7 @@ all() ->
     [bound_var, bound_tail, t_float, little_float, sean,
      kenneth, encode_binary, native, happi, size_var, wiger,
      x0_context, huge_float_field, writable_binary_matched,
-     otp_7198, unordered_bindings].
+     otp_7198, unordered_bindings, float_middle_endian].
 
 groups() -> 
     [].
@@ -106,6 +106,13 @@ t_float(Config) when is_list(Config) ->
 
     ok.
 
+float_middle_endian(Config) when is_list(Config) ->
+    F = 9007199254740990.0, % turns to -NaN when word-swapped
+    ?line fcmp(F, match_float(<<F:64/float>>, 64, 0)),
+    ?line fcmp(F, match_float(<<1:1,F:64/float,127:7>>, 64, 1)),
+    ?line fcmp(F, match_float(<<1:13,F:64/float,127:3>>, 64, 13)),
+    ok.
+
 
 fcmp(F1, F2) when (F1 - F2) / F2 < 0.0000001 -> ok.