Remove use of register r7 because llvm now issues an

error when "r7" is used (starting in commit d85b3877)

Bug: chromium:1073270
Change-Id: I7ec8112f170b98d2edaf92bc9341e738f8de07a3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2163435Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67371}

src/codegen/arm/cpu-arm.cc

@@ -37,18 +37,6 @@ V8_NOINLINE void CpuFeatures::FlushICache(void* start, size_t size) {
   register uint32_t end asm("r1") = beg + size;
   register uint32_t flg asm("r2") = 0;
 
-#ifdef __clang__
-  // This variant of the asm avoids a constant pool entry, which can be
-  // problematic when LTO'ing. It is also slightly shorter.
-  register uint32_t scno asm("r7") = __ARM_NR_cacheflush;
-
-  asm volatile("svc 0\n"
-               :
-               : "r"(beg), "r"(end), "r"(flg), "r"(scno)
-               : "memory");
-#else
-  // Use a different variant of the asm with GCC because some versions doesn't
-  // support r7 as an asm input.
   asm volatile(
       // This assembly works for both ARM and Thumb targets.
 
@@ -66,7 +54,6 @@ V8_NOINLINE void CpuFeatures::FlushICache(void* start, size_t size) {
       : "r"(beg), "r"(end), "r"(flg), [scno] "i"(__ARM_NR_cacheflush)
       : "memory");
 #endif
-#endif
 #endif  // !USE_SIMULATOR
 }