When QuickJit is enabled, disable it for methods that contain loops by default (#24252)

When QuickJit is enabled, disable it for methods that contain loops by default

Fixes https://github.com/dotnet/coreclr/issues/19751 by default when QuickJit is enabled
- Added config variable TC_QuickJitForLoops. When disabled (the default), the JIT identifies loops and explicit tail calls and switches to tier 1 JIT.
- This would prevent the possibility of spending too long in QuickJit code, but may decrease startup time a bit when QuickJit is enabled
- Removed TC_StartupTier_OptimizeCode, as now that there is TC_QuickJit, I didn't see a good use for it
- Removed references to "StartupTier" in config variables because we had previously decided not to call it that.
- When QuickJit is disabled, avoid creating native code slots for methods in non-R2R'ed modules, as tiering would be disabled for those anyway
- Marked TC_QuickJit config var as external

1 files changed, 6 insertions, 7 deletions

diff --git a/src/inc/clrconfigvalues.h b/src/inc/clrconfigvalues.h
index 3d8c26929d..ab4b8e4a05 100644
--- a/src/inc/clrconfigvalues.h
+++ b/src/inc/clrconfigvalues.h
@@ -647,13 +647,12 @@ RETAIL_CONFIG_DWORD_INFO(INTERNAL_HillClimbing_GainExponent,
 ///
 #ifdef FEATURE_TIERED_COMPILATION
 RETAIL_CONFIG_DWORD_INFO(EXTERNAL_TieredCompilation, W("TieredCompilation"), 1, "Enables tiered compilation")
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TC_QuickJit, W("TC_QuickJit"), 0, "For methods that would be jitted, enable using quick JIT when appropriate.")
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TC_StartupTier_CallCountThreshold, W("TC_StartupTier_CallCountThreshold"), 30, "Number of times a method must be called in the startup tier after which it is promoted to the next tier.")
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TC_StartupTier_CallCountingDelayMs, W("TC_StartupTier_CallCountingDelayMs"), 100, "A perpetual delay in milliseconds that is applied call counting in the startup tier and jitting at higher tiers, while there is startup-like activity.")
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TC_StartupTier_DelaySingleProcMultiplier, W("TC_StartupTier_DelaySingleProcMultiplier"), 10, "Multiplier for TC_StartupTier_CallCountingDelayMs that is applied on a single-processor machine or when the process is affinitized to a single processor.")
-
-RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_StartupTier_CallCounting, W("TC_StartupTier_CallCounting"), 1, "Enabled by default (only activates when TieredCompilation is also enabled). If disabled immediately backpatches prestub, and likely prevents any promotion to higher tiers")
-RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_StartupTier_OptimizeCode, W("TC_StartupTier_OptimizeCode"), 0, "Use optimized codegen (normally used by the optimized tier) in the startup tier")
+RETAIL_CONFIG_DWORD_INFO(EXTERNAL_TC_QuickJit, W("TC_QuickJit"), 0, "For methods that would be jitted, enable using quick JIT when appropriate.")
+RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_TC_QuickJitForLoops, W("TC_QuickJitForLoops"), 0, "When quick JIT is enabled, quick JIT may also be used for methods that contain loops.")
+RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_CallCountThreshold, W("TC_CallCountThreshold"), 30, "Number of times a method must be called in tier 0 after which it is promoted to the next tier.")
+RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_CallCountingDelayMs, W("TC_CallCountingDelayMs"), 100, "A perpetual delay in milliseconds that is applied call counting in tier 0 and jitting at higher tiers, while there is startup-like activity.")
+RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_DelaySingleProcMultiplier, W("TC_DelaySingleProcMultiplier"), 10, "Multiplier for TC_CallCountingDelayMs that is applied on a single-processor machine or when the process is affinitized to a single processor.")
+RETAIL_CONFIG_DWORD_INFO(INTERNAL_TC_CallCounting, W("TC_CallCounting"), 1, "Enabled by default (only activates when TieredCompilation is also enabled). If disabled immediately backpatches prestub, and likely prevents any promotion to higher tiers")
 #endif
 
 ///