[PATCH 2/2] tests/tcg/arm: Remove test-arm-iwmmxt test

[Peter Maydell]

The test-arm-iwmmmxt test isn't testing what it thinks it's testing.

If you run it with a CPU type that supports iwMMXt then it will crash
immediately with a SIGILL, because (even with -marm) GCC will link it
against startup code that is in Thumb mode, and no iwMMXt CPU has
Thumb:

00010338 <_start>:
   10338:       f04f 0b00       mov.w   fp, #0
   1033c:       f04f 0e00       mov.w   lr, #0

If you run it with a CPU type which does *not* support iwMMXt, which
is what 'make check-tcg' does, then QEMU will not try to handle the
insns as iwMMXt.  Instead the translator turns them into illegal
instructions.  Then in the linux-user cpu_loop() code we identify
them as FPA11 instructions inside emulate_arm_fpa11(), because the
FPA11 happened to use the same coprocessor number as these iwMMXt
insns.  So we execute a completely different set of FPA11 insns,
which means we don't crash, but we will print garbage to stdout.
Then the test binary always exits with a 0 return code, so 'make
check-tcg' thinks the test passes.

Modern gnueabihf toolchains assume in their startup code that the CPU
is not so old as to not support Thumb, so there's no way to get them
to generate a binary that actually does what the test wants.  Since
we're deprecating iwMMXt emulation anyway, it's not worth trying to
salvage the test case to get it to really test the iwMMXt insns.

Delete the test entirely.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 tests/tcg/arm/Makefile.target   |  7 -----
 tests/tcg/arm/README            |  5 ----
 tests/tcg/arm/test-arm-iwmmxt.S | 49 ---------------------------------
 3 files changed, 61 deletions(-)
 delete mode 100644 tests/tcg/arm/test-arm-iwmmxt.S

diff --git a/tests/tcg/arm/Makefile.target b/tests/tcg/arm/Makefile.target
index 06ddf3e04fc..99a953b6671 100644
--- a/tests/tcg/arm/Makefile.target
+++ b/tests/tcg/arm/Makefile.target
@@ -20,13 +20,6 @@ ARM_TESTS = hello-arm
 hello-arm: CFLAGS+=-marm -ffreestanding -fno-stack-protector
 hello-arm: LDFLAGS+=-nostdlib
 
-# IWMXT floating point extensions
-ARM_TESTS += test-arm-iwmmxt
-# Clang assembler does not support IWMXT, so use the external assembler.
-test-arm-iwmmxt: CFLAGS += -marm -march=iwmmxt -mabi=aapcs -mfpu=fpv4-sp-d16 
$(CROSS_CC_HAS_FNIA)
-test-arm-iwmmxt: test-arm-iwmmxt.S
-       $(CC) $(CFLAGS) -Wa,--noexecstack $< -o $@ $(LDFLAGS)
-
 # Float-convert Tests
 ARM_TESTS += fcvt
 fcvt: LDFLAGS += -lm
diff --git a/tests/tcg/arm/README b/tests/tcg/arm/README
index e6307116e23..aceccc127f7 100644
--- a/tests/tcg/arm/README
+++ b/tests/tcg/arm/README
@@ -4,8 +4,3 @@ hello-arm
 ---------
 
 A very simple inline assembly, write syscall based hello world
-
-test-arm-iwmmxt
----------------
-
-A simple test case for older iwmmxt extended ARMs
diff --git a/tests/tcg/arm/test-arm-iwmmxt.S b/tests/tcg/arm/test-arm-iwmmxt.S
deleted file mode 100644
index d647f9404ae..00000000000
--- a/tests/tcg/arm/test-arm-iwmmxt.S
+++ /dev/null
@@ -1,49 +0,0 @@
-@ Checks whether iwMMXt is functional.
-.code  32
-.globl main
-
-main:
-ldr    r0, =data0
-ldr    r1, =data1
-ldr    r2, =data2
-#ifndef FPA
-wldrd  wr0, [r0, #0]
-wldrd  wr1, [r0, #8]
-wldrd  wr2, [r1, #0]
-wldrd  wr3, [r1, #8]
-wsubb  wr2, wr2, wr0
-wsubb  wr3, wr3, wr1
-wldrd  wr0, [r2, #0]
-wldrd  wr1, [r2, #8]
-waddb  wr0, wr0, wr2
-waddb  wr1, wr1, wr3
-wstrd  wr0, [r2, #0]
-wstrd  wr1, [r2, #8]
-#else
-ldfe   f0, [r0, #0]
-ldfe   f1, [r0, #8]
-ldfe   f2, [r1, #0]
-ldfe   f3, [r1, #8]
-adfdp  f2, f2, f0
-adfdp  f3, f3, f1
-ldfe   f0, [r2, #0]
-ldfe   f1, [r2, #8]
-adfd   f0, f0, f2
-adfd   f1, f1, f3
-stfe   f0, [r2, #0]
-stfe   f1, [r2, #8]
-#endif
-mov    r0, #1
-mov    r1, r2
-mov    r2, #0x11
-swi    #0x900004
-mov    r0, #0
-swi    #0x900001
-
-.data
-data0:
-.string        "aaaabbbbccccdddd"
-data1:
-.string        "bbbbccccddddeeee"
-data2:
-.string        "hvLLWs\x1fsdrs9\x1fNJ-\n"
-- 
2.34.1