diff --git a/libc/src/__support/threads/linux/CMakeLists.txt b/libc/src/__support/threads/linux/CMakeLists.txt
index fa11458f99b6c..47598d98c9886 100644
--- a/libc/src/__support/threads/linux/CMakeLists.txt
+++ b/libc/src/__support/threads/linux/CMakeLists.txt
@@ -88,7 +88,7 @@ add_object_library(
     libc.src.__support.error_or
     libc.src.__support.threads.thread_common
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fno-omit-frame-pointer # This allows us to sniff out the thread args from
                             # the new thread's stack reliably.
     -Wno-frame-address      # Yes, calling __builtin_return_address with a
diff --git a/libc/src/complex/generic/CMakeLists.txt b/libc/src/complex/generic/CMakeLists.txt
index a63871b32afbf..a3da781c60237 100644
--- a/libc/src/complex/generic/CMakeLists.txt
+++ b/libc/src/complex/generic/CMakeLists.txt
@@ -5,7 +5,7 @@ add_entrypoint_object(
   HDRS
     ../creal.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -18,7 +18,7 @@ add_entrypoint_object(
   HDRS
     ../crealf.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -31,7 +31,7 @@ add_entrypoint_object(
   HDRS
     ../creall.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -44,7 +44,7 @@ add_entrypoint_object(
   HDRS
     ../crealf16.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -59,7 +59,7 @@ add_entrypoint_object(
   HDRS
     ../crealf128.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -74,7 +74,7 @@ add_entrypoint_object(
   HDRS
     ../cimag.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -87,7 +87,7 @@ add_entrypoint_object(
   HDRS
     ../cimagf.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -100,7 +100,7 @@ add_entrypoint_object(
   HDRS
     ../cimagl.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -113,7 +113,7 @@ add_entrypoint_object(
   HDRS
     ../cimagf16.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
@@ -128,7 +128,7 @@ add_entrypoint_object(
   HDRS
     ../cimagf128.h
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.CPP.bit
     libc.src.__support.complex_type
diff --git a/libc/src/pthread/CMakeLists.txt b/libc/src/pthread/CMakeLists.txt
index 8480fd8942222..c8c66805667fa 100644
--- a/libc/src/pthread/CMakeLists.txt
+++ b/libc/src/pthread/CMakeLists.txt
@@ -333,7 +333,7 @@ add_entrypoint_object(
     libc.src.pthread.pthread_attr_getstack
     libc.src.errno.errno
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fno-omit-frame-pointer
 )
 
diff --git a/libc/src/setjmp/riscv/CMakeLists.txt b/libc/src/setjmp/riscv/CMakeLists.txt
index 464144758cbbe..c68e318a0f08b 100644
--- a/libc/src/setjmp/riscv/CMakeLists.txt
+++ b/libc/src/setjmp/riscv/CMakeLists.txt
@@ -7,7 +7,7 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.types.jmp_buf
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fomit-frame-pointer
 )
 
@@ -20,6 +20,6 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.types.jmp_buf
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fomit-frame-pointer
 )
diff --git a/libc/src/setjmp/x86_64/CMakeLists.txt b/libc/src/setjmp/x86_64/CMakeLists.txt
index b5b0d9ba65599..96d5751bc81dd 100644
--- a/libc/src/setjmp/x86_64/CMakeLists.txt
+++ b/libc/src/setjmp/x86_64/CMakeLists.txt
@@ -7,7 +7,7 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.types.jmp_buf
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
 )
 
 add_entrypoint_object(
@@ -19,6 +19,6 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.types.jmp_buf
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fomit-frame-pointer
 )
diff --git a/libc/src/signal/linux/CMakeLists.txt b/libc/src/signal/linux/CMakeLists.txt
index e314242dc376f..f7457d31cf4f8 100644
--- a/libc/src/signal/linux/CMakeLists.txt
+++ b/libc/src/signal/linux/CMakeLists.txt
@@ -41,7 +41,7 @@ add_object_library(
     __restore.cpp
   COMPILE_OPTIONS
     -fomit-frame-pointer
-    -O3
+    ${libc_opt_high_flag}
     -Wframe-larger-than=0
     -Wno-attributes
     # asan creates asan.module_ctor which uses stack space, causing warnings.
diff --git a/libc/src/stdfix/CMakeLists.txt b/libc/src/stdfix/CMakeLists.txt
index 238b86728188a..815f739d23efa 100644
--- a/libc/src/stdfix/CMakeLists.txt
+++ b/libc/src/stdfix/CMakeLists.txt
@@ -10,7 +10,7 @@ foreach(suffix IN ITEMS hr r lr hk k lk)
     SRCS
       abs${suffix}.cpp
     COMPILE_OPTIONS
-      -O3
+      ${libc_opt_high_flag}
     DEPENDS
       libc.src.__support.fixed_point.fx_bits
   )
@@ -24,7 +24,7 @@ foreach(suffix IN ITEMS uhr ur ulr uhk uk)
     SRCS
       sqrt${suffix}.cpp
     COMPILE_OPTIONS
-      -O3
+      ${libc_opt_high_flag}
     DEPENDS
       libc.src.__support.fixed_point.sqrt
   )
@@ -38,7 +38,7 @@ foreach(suffix IN ITEMS hr r lr hk k lk uhr ur ulr uhk uk ulk)
     SRCS
       round${suffix}.cpp
     COMPILE_OPTIONS
-      -O3
+      ${libc_opt_high_flag}
     DEPENDS
       libc.src.__support.fixed_point.fx_bits
   )
@@ -62,7 +62,7 @@ add_entrypoint_object(
   SRCS
     uhksqrtus.cpp
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.fixed_point.sqrt
 )
@@ -74,7 +74,7 @@ add_entrypoint_object(
   SRCS
     uksqrtui.cpp
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.fixed_point.sqrt
 )
@@ -86,7 +86,7 @@ add_entrypoint_object(
   SRCS
     exphk.cpp
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.fixed_point.fx_rep
     libc.src.__support.CPP.bit
@@ -99,7 +99,7 @@ add_entrypoint_object(
   SRCS
     expk.cpp
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
   DEPENDS
     libc.src.__support.fixed_point.fx_rep
     libc.src.__support.CPP.bit
diff --git a/libc/src/string/CMakeLists.txt b/libc/src/string/CMakeLists.txt
index d6e300754d4f9..8fe1226dd6a7a 100644
--- a/libc/src/string/CMakeLists.txt
+++ b/libc/src/string/CMakeLists.txt
@@ -506,7 +506,7 @@ function(add_implementation name impl_name)
     SRCS ${ADD_IMPL_SRCS}
     HDRS ${ADD_IMPL_HDRS}
     DEPENDS ${ADD_IMPL_DEPENDS}
-    COMPILE_OPTIONS -O3 ${ADD_IMPL_COMPILE_OPTIONS}
+    COMPILE_OPTIONS ${libc_opt_high_flag} ${ADD_IMPL_COMPILE_OPTIONS}
   )
   get_fq_target_name(${impl_name} fq_target_name)
   set_target_properties(${fq_target_name} PROPERTIES REQUIRE_CPU_FEATURES "${ADD_IMPL_REQUIRE}")
diff --git a/libc/src/threads/CMakeLists.txt b/libc/src/threads/CMakeLists.txt
index c33be265369fe..17dea3920a07a 100644
--- a/libc/src/threads/CMakeLists.txt
+++ b/libc/src/threads/CMakeLists.txt
@@ -24,7 +24,7 @@ add_entrypoint_object(
     libc.include.threads
     libc.src.errno.errno
   COMPILE_OPTIONS
-    -O3
+    ${libc_opt_high_flag}
     -fno-omit-frame-pointer # This allows us to sniff out the thread args from
                             # the new thread's stack reliably.
 )
diff --git a/libc/test/src/math/smoke/LdExpTest.h b/libc/test/src/math/smoke/LdExpTest.h
index 42e4c6a3a5184..094cc7e4e9e7d 100644
--- a/libc/test/src/math/smoke/LdExpTest.h
+++ b/libc/test/src/math/smoke/LdExpTest.h
@@ -50,7 +50,8 @@ class LdExpTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
 
     if constexpr (sizeof(U) < sizeof(long) || sizeof(long) == sizeof(int))
       return;
-    long long_exp_array[4] = {LONG_MIN, INT_MIN - 1L, INT_MAX + 1L, LONG_MAX};
+    long long_exp_array[4] = {LONG_MIN, static_cast<long>(INT_MIN - 1LL),
+                              static_cast<long>(INT_MAX + 1LL), LONG_MAX};
     for (long exp : long_exp_array) {
       ASSERT_FP_EQ(zero, func(zero, exp));
       ASSERT_FP_EQ(neg_zero, func(neg_zero, exp));