Add an 'optinfo' build target

The 'optinfo' build target asks GCC to print optimizations that
could not be performed to local 'missing.txt' files; these will
appear in each repsective subdirectory having source files.

Both GCC and Clang will now print Verbose vectorization information
during the build process, often describing why vectorization
cannot be performed.

This commit also enables basic instruction and math vectorization
for both the 'release' and 'optinfo' targets. This includes making
use of altivec instructions (available on all powerpc processors),
and at a minimum sse4.2 on all x86_64 processors (circa-2008+ AMD
and Intel CPUs).

Vectorization is also re-enabled for GCC FDO builds, which would
otherwise be disabled when we switch to -O2 optimizations.

.gitignore

@@ -58,6 +58,7 @@ make.log
 .previous_build
 .current_build
 *.defines
+missed.txt
 
 # Visual Studio
 .vs

scripts/automator/build/clang-defaults

@@ -2,21 +2,26 @@
 cc="${ccache}clang${postfix}"
 cxx="${ccache}clang++${postfix}"
 
-# Flag additions
-TYPES+=(debug warnmore pgotrain)
-cflags_release=("${cflags[@]}" -O3)
-cflags_debug=("${cflags[@]}" -g -fno-omit-frame-pointer)
-cflags_pgotrain=("${cflags_debug[@]}" -fprofile-instr-generate -fcoverage-mapping)
-cflags_warnmore=("${cflags_debug[@]}" -Wextra -Wshadow -Wcast-align -Wunused
-                 -Woverloaded-virtual -Wpedantic -Wconversion -Wsign-conversion
-                 -Wdouble-promotion -Wformat=2)
-cxxonly_warnmore=(-Wnon-virtual-dtor -Woverloaded-virtual)
-
 # Colorize output only for interactive shells
 if [[ $- == *i* ]]; then
 	cflags+=(-fcolor-diagnostics)
 fi
 
+# Release-type additions
+TYPES+=(release debug warnmore pgotrain optinfo)
+
+# Note: -fno-math-errno allows better optimization of C/C++ math library functions
+cflags_release+=("${cflags[@]}" -DNDEBUG -O3 -fno-math-errno -fno-strict-aliasing)
+
+cflags_debug+=("${cflags[@]}" -g -fno-omit-frame-pointer)
+cflags_pgotrain+=("${cflags_debug[@]}" -fprofile-instr-generate -fcoverage-mapping)
+cflags_warnmore+=("${cflags_debug[@]}" -Wextra -Wshadow -Wcast-align -Wunused
+                  -Woverloaded-virtual -Wpedantic -Wconversion -Wsign-conversion
+                  -Wdouble-promotion -Wformat=2)
+cxxonly_warnmore+=(-Wnon-virtual-dtor -Woverloaded-virtual)
+cflags_optinfo+=("${cflags_release[@]}" -Rpass-analysis=loop-vectorize
+                 -gline-tables-only -gcolumn-info)
+
 # Modifier additions
 MODIFIERS=(fdo)
 cflags_fdo=("-fprofile-sample-use=${FDO_FILE:-${repo_root}/current.afdo}")

scripts/automator/build/compiler-defaults

@@ -10,10 +10,6 @@ cxxonly=("")
 ldflags=("")
 libs=("")
 
-# Builds for all compilers
-TYPES=(release)
-cflags_release=("${cflags[@]}" -DNDEBUG)
-
 # Use ccache if it's available
 if command -v ccache &> /dev/null; then
 	ccache="ccache "

scripts/automator/build/gcc-darwin_x86_64

@@ -2,6 +2,11 @@
 ar="ar"
 ranlib="ranlib"
 
+# The oldest processor supported by macOS is nehalem, so we can safely
+# enable its full instruction set give all subsequent processors support it.
+cflags_release+=(-march=nehalem)
+cflags_optinfo+=(-march=nehalem)
+
 # Build additions
 TYPES+=(asan uasan usan tsan)
 cflags_asan=("${cflags_debug[@]}" -fsanitize=address)

scripts/automator/build/gcc-defaults

@@ -5,19 +5,28 @@ cxx="${ccache}g++${postfix}"
 ld="gcc${postfix}"
 ranlib="gcc-ranlib${postfix}"
 
-# Flag additions
-TYPES+=(debug warnmore pgotrain fdotrain)
+# Release-type additions
+TYPES+=(release debug warnmore pgotrain fdotrain optinfo)
 
 cflags+=(-fstack-protector -fdiagnostics-color=auto)
-cflags_debug=("${cflags[@]}" -g -fno-omit-frame-pointer)
-cflags_release=("${cflags[@]}" -DNDEBUG -O3 -ffunction-sections -fdata-sections)
-cflags_pgotrain=("${cflags_debug[@]}" -pg)
-cflags_warnmore=("${cflags_debug[@]}" -pedantic -Wcast-align -Wdouble-promotion
-                 -Wduplicated-branches -Wduplicated-cond -Wextra -Wformat=2
-                 -Wlogical-op -Wmisleading-indentation -Wnull-dereference
-                 -Wshadow -Wunused)
-cxxonly_warnmore=(-Weffc++ -Wnon-virtual-dtor -Woverloaded-virtual -Wuseless-cast)
-cflags_fdotrain=("${cflags[@]}" -DNDEBUG -g1 -fno-omit-frame-pointer)
+cflags_debug+=("${cflags[@]}" -g -fno-omit-frame-pointer)
+
+# Note: associative-math is needed for vectorization of floating point
+#       calculations, which also relies on no-signed-zeros and
+#       no-trapping-math.
+cflags_release+=("${cflags[@]}" -DNDEBUG -O3 -fno-strict-aliasing
+                 -fno-signed-zeros -fno-trapping-math -fassociative-math
+                 -frename-registers -ffunction-sections -fdata-sections)
+
+cflags_pgotrain+=("${cflags_debug[@]}" -pg -ftree-vectorize)
+cflags_warnmore+=("${cflags_debug[@]}" -pedantic -Wcast-align -Wdouble-promotion
+                  -Wduplicated-branches -Wduplicated-cond -Wextra -Wformat=2
+                  -Wlogical-op -Wmisleading-indentation -Wnull-dereference
+                  -Wshadow -Wunused)
+cxxonly_warnmore+=(-Weffc++ -Wnon-virtual-dtor -Woverloaded-virtual -Wuseless-cast)
+cflags_fdotrain+=("${cflags[@]}" -DNDEBUG -g1 -fno-omit-frame-pointer)
+cflags_optinfo+=("${cflags_release[@]}" -fopt-info-missed
+                 -ftree-vectorizer-verbose=6)
 
 # Modifier additions
 MODIFIERS=(fdo)

scripts/automator/build/gcc-linux_x86_64

@@ -1,6 +1,11 @@
 # Tool additions
 ldflags+=(-Wl,--as-needed)
 
+# Enable math vectorizions using instructions avaiable in circa-2008+ CPUs
+x86_math=(-mfpmath=sse -msse4.2)
+cflags_release+=("${x86_math[@]}")
+cflags_optinfo+=("${x86_math[@]}")
+
 # Build additions
 TYPES+=(asan uasan usan tsan)
 cflags_asan=("${cflags_debug[@]}" -fsanitize=address)

scripts/automator/build/gcc-msys_nt_x86_64

@@ -1,3 +1,8 @@
+# Enable math vectorizations using instructions avaiable in circa-2008+ CPUs
+x86_math=(-mfpmath=sse -msse4.2)
+cflags_release+=("${x86_math[@]}")
+cflags_optinfo+=("${x86_math[@]}")
+
 # Flag additions
 ldflags+=(-Wl,--as-needed -static-libgcc -static-libstdc++)