diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -797,12 +797,7 @@
                                     std::string ProfileFile,
                                     std::string ProfileRemappingFile) {
   assert(Level != OptimizationLevel::O0 && "Not expecting O0 here!");
-  // Generally running simplification passes and the inliner with an high
-  // threshold results in smaller executables, but there may be cases where
-  // the size grows, so let's be conservative here and skip this simplification
-  // at -Os/Oz. We will not do this  inline for context sensistive PGO (when
-  // IsCS is true).
-  if (!Level.isOptimizingForSize() && !IsCS && !DisablePreInliner) {
+  if (!IsCS && !DisablePreInliner) {
     InlineParams IP;
 
     IP.DefaultThreshold = PreInlineThreshold;
@@ -810,7 +805,7 @@
     // FIXME: The hint threshold has the same value used by the regular inliner.
     // This should probably be lowered after performance testing.
     // FIXME: this comment is cargo culted from the old pass manager, revisit).
-    IP.HintThreshold = 325;
+    IP.HintThreshold = Level.isOptimizingForSize() ? PreInlineThreshold : 325;
     ModuleInlinerWrapperPass MIWP(IP, DebugLogging);
     CGSCCPassManager &CGPipeline = MIWP.getPM();
 
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -330,10 +330,8 @@
     return;
 
   // Perform the preinline and cleanup passes for O1 and above.
-  // And avoid doing them if optimizing for size.
   // We will not do this inline for context sensitive PGO (when IsCS is true).
-  if (OptLevel > 0 && SizeLevel == 0 && !DisablePreInliner &&
-      PGOSampleUse.empty() && !IsCS) {
+  if (OptLevel > 0 && !DisablePreInliner && PGOSampleUse.empty() && !IsCS) {
     // Create preinline pass. We construct an InlineParams object and specify
     // the threshold here to avoid the command line options of the regular
     // inliner to influence pre-inlining. The only fields of InlineParams we
@@ -342,7 +340,7 @@
     IP.DefaultThreshold = PreInlineThreshold;
     // FIXME: The hint threshold has the same value used by the regular inliner.
     // This should probably be lowered after performance testing.
-    IP.HintThreshold = 325;
+    IP.HintThreshold = SizeLevel > 0 ? PreInlineThreshold : 325;
 
     MPM.add(createFunctionInliningPass(IP));
     MPM.add(createSROAPass());