diff --git a/libc/test/UnitTest/FEnvSafeTest.cpp b/libc/test/UnitTest/FEnvSafeTest.cpp
index 73cf6a856c77..0747b6224cf8 100644
--- a/libc/test/UnitTest/FEnvSafeTest.cpp
+++ b/libc/test/UnitTest/FEnvSafeTest.cpp
@@ -115,7 +115,8 @@ void FEnvSafeTest::expect_fenv_eq(const fenv_t &before_fenv,
 
 #else
   // No arch-specific `fenv_t` support, so nothing to compare.
-
+  (void)before_fenv;
+  (void)after_fenv;
 #endif
 }
 
diff --git a/libc/test/include/complex_test.cpp b/libc/test/include/complex_test.cpp
index 6f900aa4fb67..7c8e9da49256 100644
--- a/libc/test/include/complex_test.cpp
+++ b/libc/test/include/complex_test.cpp
@@ -27,7 +27,7 @@ TEST(LlvmLibcComplexTest, CMPLXMacro) {
   EXPECT_CFP_EQ(CMPLXL(1.0l, 0), 1.0l);
 
 #ifdef LIBC_TYPES_HAS_CFLOAT16
-  EXPECT_CFP_EQ(CMPLXF16(0, 1.0), I);
+  EXPECT_CFP_EQ(CMPLXF16(0, 1.0), CMPLXF16(__real__ I, __imag__ I));
   EXPECT_CFP_EQ(CMPLXF16(1.0, 0), 1.0);
 #endif // LIBC_TYPES_HAS_CFLOAT16
 
diff --git a/libc/test/integration/src/__support/GPU/fixedstack_test.cpp b/libc/test/integration/src/__support/GPU/fixedstack_test.cpp
index fde51df325ab..40d713c64b1d 100644
--- a/libc/test/integration/src/__support/GPU/fixedstack_test.cpp
+++ b/libc/test/integration/src/__support/GPU/fixedstack_test.cpp
@@ -37,7 +37,7 @@ void run() {
     ;
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   run();
 
   return 0;
diff --git a/libc/test/integration/src/__support/GPU/match.cpp b/libc/test/integration/src/__support/GPU/match.cpp
index 70c22b7f3a91..fe6751b2dcda 100644
--- a/libc/test/integration/src/__support/GPU/match.cpp
+++ b/libc/test/integration/src/__support/GPU/match.cpp
@@ -30,7 +30,7 @@ static void test_match() {
 #endif
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   if (gpu::get_thread_id() >= gpu::get_lane_size())
     return 0;
 
diff --git a/libc/test/integration/src/__support/GPU/scan_reduce.cpp b/libc/test/integration/src/__support/GPU/scan_reduce.cpp
index 1d50e1f99bf3..3861a612c587 100644
--- a/libc/test/integration/src/__support/GPU/scan_reduce.cpp
+++ b/libc/test/integration/src/__support/GPU/scan_reduce.cpp
@@ -97,7 +97,7 @@ static void test_scan_divergent() {
   }
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   if (gpu::get_thread_id() >= gpu::get_lane_size())
     return 0;
 
diff --git a/libc/test/integration/src/__support/GPU/shuffle.cpp b/libc/test/integration/src/__support/GPU/shuffle.cpp
index c346a2eb3f0c..01a2d04643ec 100644
--- a/libc/test/integration/src/__support/GPU/shuffle.cpp
+++ b/libc/test/integration/src/__support/GPU/shuffle.cpp
@@ -16,14 +16,14 @@ using namespace LIBC_NAMESPACE;
 // Each iteration reduces the width, so it will broadcast to a subset we check.
 static void test_shuffle() {
   uint64_t mask = gpu::get_lane_mask();
-  EXPECT_EQ(cpp::popcount(mask), gpu::get_lane_size());
+  EXPECT_EQ(static_cast<uint32_t>(cpp::popcount(mask)), gpu::get_lane_size());
 
   uint32_t x = gpu::get_lane_id();
   for (uint32_t width = gpu::get_lane_size(); width > 0; width /= 2)
     EXPECT_EQ(gpu::shuffle(mask, 0, x, width), (x / width) * width);
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   if (gpu::get_thread_id() >= gpu::get_lane_size())
     return 0;
 
diff --git a/libc/test/integration/src/stdio/gpu/printf_test.cpp b/libc/test/integration/src/stdio/gpu/printf_test.cpp
index 5f78737a2aca..e787d80ce39c 100644
--- a/libc/test/integration/src/stdio/gpu/printf_test.cpp
+++ b/libc/test/integration/src/stdio/gpu/printf_test.cpp
@@ -16,7 +16,7 @@ using namespace LIBC_NAMESPACE;
 
 FILE *file = LIBC_NAMESPACE::fopen("testdata/test_data.txt", "w");
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   ASSERT_TRUE(file && "failed to open file");
   // Check basic printing.
   int written = 0;
diff --git a/libc/test/integration/src/stdlib/gpu/malloc_stress.cpp b/libc/test/integration/src/stdlib/gpu/malloc_stress.cpp
index 4c540a8a57ca..dc68fd0b7fa4 100644
--- a/libc/test/integration/src/stdlib/gpu/malloc_stress.cpp
+++ b/libc/test/integration/src/stdlib/gpu/malloc_stress.cpp
@@ -30,11 +30,11 @@ static inline uint32_t xorshift32(uint32_t &state) {
 
 static inline void use(uint8_t *ptr, uint32_t size) {
   EXPECT_NE(ptr, nullptr);
-  for (int i = 0; i < size; ++i)
+  for (uint32_t i = 0; i < size; ++i)
     ptr[i] = uint8_t(i + gpu::get_thread_id());
 
   // Try to detect if some other thread manages to clobber our memory.
-  for (int i = 0; i < size; ++i)
+  for (uint32_t i = 0; i < size; ++i)
     EXPECT_EQ(ptr[i], uint8_t(i + gpu::get_thread_id()));
 }
 
diff --git a/libc/test/integration/startup/gpu/init_fini_array_test.cpp b/libc/test/integration/startup/gpu/init_fini_array_test.cpp
index ceedd5fc8135..31af074063c8 100644
--- a/libc/test/integration/startup/gpu/init_fini_array_test.cpp
+++ b/libc/test/integration/startup/gpu/init_fini_array_test.cpp
@@ -53,7 +53,7 @@ __attribute__((destructor(101))) void reset_initval() {
   initval = 0;
 }
 
-TEST_MAIN(int argc, char **argv, char **env) {
+TEST_MAIN(int, char **, char **) {
   ASSERT_EQ(global.get(GLOBAL_INDEX), INITVAL_INITIALIZER);
   ASSERT_EQ(initval, INITVAL_INITIALIZER);
   return 0;
diff --git a/libc/test/integration/startup/gpu/rpc_interface_test.cpp b/libc/test/integration/startup/gpu/rpc_interface_test.cpp
index 0b7ff549fe39..05b58d1f937c 100644
--- a/libc/test/integration/startup/gpu/rpc_interface_test.cpp
+++ b/libc/test/integration/startup/gpu/rpc_interface_test.cpp
@@ -57,7 +57,7 @@ static void test_interface(bool end_with_send) {
   ASSERT_TRUE(cnt == 9 && "Invalid number of increments");
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   test_interface(true);
   test_interface(false);
 
diff --git a/libc/test/integration/startup/gpu/rpc_test.cpp b/libc/test/integration/startup/gpu/rpc_test.cpp
index 018745a9e29c..1069353f3a9c 100644
--- a/libc/test/integration/startup/gpu/rpc_test.cpp
+++ b/libc/test/integration/startup/gpu/rpc_test.cpp
@@ -39,7 +39,7 @@ static void test_noop(uint8_t data) {
   });
 }
 
-TEST_MAIN(int argc, char **argv, char **envp) {
+TEST_MAIN(int, char **, char **) {
   test_add_simple();
 
   if (gpu::get_thread_id() % 2)
diff --git a/libc/test/src/stdio/fopen_test.cpp b/libc/test/src/stdio/fopen_test.cpp
index 3f651f755e7f..60852ddf0938 100644
--- a/libc/test/src/stdio/fopen_test.cpp
+++ b/libc/test/src/stdio/fopen_test.cpp
@@ -15,7 +15,7 @@
 #include "test/UnitTest/Test.h"
 
 TEST(LlvmLibcFOpenTest, PrintToFile) {
-  int result;
+  size_t result;
 
   FILE *file =
       LIBC_NAMESPACE::fopen(APPEND_LIBC_TEST("testdata/test.txt"), "w");
@@ -23,7 +23,7 @@ TEST(LlvmLibcFOpenTest, PrintToFile) {
 
   static constexpr char STRING[] = "A simple string written to a file\n";
   result = LIBC_NAMESPACE::fwrite(STRING, 1, sizeof(STRING) - 1, file);
-  EXPECT_GE(result, 0);
+  EXPECT_GE(result, size_t(0));
 
   ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
 
diff --git a/libc/test/src/stdlib/strtof_test.cpp b/libc/test/src/stdlib/strtof_test.cpp
index 6df1ddda93bf..1cd2b165ea91 100644
--- a/libc/test/src/stdlib/strtof_test.cpp
+++ b/libc/test/src/stdlib/strtof_test.cpp
@@ -23,7 +23,8 @@ class LlvmLibcStrToFTest : public LIBC_NAMESPACE::testing::ErrnoCheckingTest,
                            ForceRoundingModeTest<RoundingMode::Nearest> {
 public:
   void run_test(const char *inputString, const ptrdiff_t expectedStrLen,
-                const uint32_t expectedRawData, const int expectedErrno = 0) {
+                const uint32_t expectedRawData,
+                [[maybe_unused]] const int expectedErrno = 0) {
     // expectedRawData is the expected float result as a uint32_t, organized
     // according to IEEE754:
     //
diff --git a/libc/test/src/stdlib/strtold_test.cpp b/libc/test/src/stdlib/strtold_test.cpp
index eb4056dc7ba6..79fe682e81a6 100644
--- a/libc/test/src/stdlib/strtold_test.cpp
+++ b/libc/test/src/stdlib/strtold_test.cpp
@@ -78,7 +78,7 @@ public:
     using FPBits = LIBC_NAMESPACE::fputil::FPBits<long double>;
     FPBits expected_fp =
         FPBits(static_cast<FPBits::StorageType>(expectedRawData));
-    const int expected_errno = expectedErrno;
+    [[maybe_unused]] const int expected_errno = expectedErrno;
 
     long double result = LIBC_NAMESPACE::strtold(inputString, &str_end);
 
diff --git a/libc/test/src/time/mktime_test.cpp b/libc/test/src/time/mktime_test.cpp
index 4942ca88f961..d7fc635043fb 100644
--- a/libc/test/src/time/mktime_test.cpp
+++ b/libc/test/src/time/mktime_test.cpp
@@ -36,7 +36,8 @@ TEST(LlvmLibcMkTime, FailureSetsErrno) {
                     .tm_wday = 0,
                     .tm_yday = 0,
                     .tm_isdst = 0};
-  EXPECT_THAT(LIBC_NAMESPACE::mktime(&tm_data), Fails(EOVERFLOW));
+  EXPECT_THAT(static_cast<int>(LIBC_NAMESPACE::mktime(&tm_data)),
+              Fails(EOVERFLOW));
 }
 
 TEST(LlvmLibcMkTime, InvalidSeconds) {
@@ -51,7 +52,8 @@ TEST(LlvmLibcMkTime, InvalidSeconds) {
                       .tm_wday = 0,
                       .tm_yday = 0,
                       .tm_isdst = 0};
-    EXPECT_THAT(LIBC_NAMESPACE::mktime(&tm_data), Succeeds(-1));
+    EXPECT_THAT(static_cast<int>(LIBC_NAMESPACE::mktime(&tm_data)),
+                Succeeds(-1));
     EXPECT_TM_EQ((tm{.tm_sec = 59,
                      .tm_min = 59,
                      .tm_hour = 23,