Rollup merge of #41080 - cuviper:generic-powerpc, r=alexcrichton

dist-powerpc-linux: use a pure 32-bit CPU profile

With `-mcpu=power4`, code might use instructions like `fcfid`, excluding
older CPUs like the PowerPC G4, which apparently some users would like
to use.  The generic `-mcpu=powerpc` should stick to pure 32-bit PowerPC
instructions.

Fixes rust-lang/cargo#3852.

src/ci/docker/README.md

@@ -152,18 +152,13 @@ For targets: `powerpc-unknown-linux-gnu`
 - Path and misc options > Patches origin = Bundled, then local
 - Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = powerpc
-- Target options > Emit assembly for CPU = power4 -- (+)
-- Target options > Tune for CPU = power6 -- (+)
+- Target options > Emit assembly for CPU = powerpc -- pure 32-bit PowerPC
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
 - C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
 - C compiler > gcc version = 4.9.3
-- C compiler > Core gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
-- C compiler > gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
-(+) These CPU options match the configuration of the toolchains in RHEL6.
-
 ## `powerpc64-linux-gnu.config`
 
 For targets: `powerpc64-unknown-linux-gnu`

src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config

@@ -101,8 +101,8 @@ CT_ARCH_SUPPORTS_WITH_FLOAT=y
 CT_ARCH_DEFAULT_BE=y
 CT_ARCH_DEFAULT_32=y
 CT_ARCH_ABI=""
-CT_ARCH_CPU="power4"
-CT_ARCH_TUNE="power6"
+CT_ARCH_CPU="powerpc"
+CT_ARCH_TUNE=""
 CT_ARCH_BE=y
 # CT_ARCH_LE is not set
 CT_ARCH_32=y
@@ -391,8 +391,8 @@ CT_CC_GCC_HAS_LIBSANITIZER=y
 CT_CC_GCC_VERSION="4.9.3"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
-CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY="--with-cpu-32=power4 --with-cpu=default32"
-CT_CC_GCC_EXTRA_CONFIG_ARRAY="--with-cpu-32=power4 --with-cpu=default32"
+CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
+CT_CC_GCC_EXTRA_CONFIG_ARRAY=""
 CT_CC_GCC_EXTRA_ENV_ARRAY=""
 CT_CC_GCC_STATIC_LIBSTDCXX=y
 # CT_CC_GCC_SYSTEM_ZLIB is not set