Thread (63 messages) 63 messages, 11 authors, 2017-11-09

[PATCH 07/15] arm64: use -mno-implicit-float instead of -mgeneral-regs-only

From: mark.rutland@arm.com (Mark Rutland)
Date: 2017-11-03 18:03:03
Also in: lkml

On Fri, Nov 03, 2017 at 10:11:52AM -0700, Sami Tolvanen wrote:
From: Greg Hackmann <redacted>

LLVM bug 30792 causes clang's AArch64 backend to crash compiling
arch/arm64/crypto/aes-ce-cipher.c.  Replacing -mgeneral-regs-only with
-mno-implicit-float is the suggested workaround.

Signed-off-by: Greg Hackmann <redacted>
Cc: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Ah, so I guess this is what I was hitting when testing with clang 5.0.0.

I was under the impression that this series was jsut enablnig LTO
support, not clang support generally.

It would be much nicer if we could depend on a fixed clang to start
with...

Thanks,
Mark.
quoted hunk ↗ jump to hunk
---
 arch/arm64/Makefile | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 939b310913cf..eb6f3c9ec6cb 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -45,7 +45,13 @@ $(warning Detected assembler with broken .inst; disassembly will be unreliable)
   endif
 endif
 
-KBUILD_CFLAGS	+= -mgeneral-regs-only $(lseinstr) $(brokengasinst)
+ifeq ($(cc-name),clang)
+# This is a workaround for https://bugs.llvm.org/show_bug.cgi?id=30792.
+KBUILD_CFLAGS	+= -mno-implicit-float
+else
+KBUILD_CFLAGS	+= -mgeneral-regs-only
+endif
+KBUILD_CFLAGS	+= $(lseinstr) $(brokengasinst)
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
 KBUILD_CFLAGS	+= $(call cc-option, -mpc-relative-literal-loads)
 KBUILD_AFLAGS	+= $(lseinstr) $(brokengasinst)
-- 
2.15.0.403.gc27cc4dac6-goog


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