From cfebab305aff942b42acdcb8697b109806a78ef0 Mon Sep 17 00:00:00 2001
From: Andy Ayers <andya@microsoft.com>
Date: Fri, 5 May 2023 20:00:53 -0700
Subject: [PATCH] JIT: produce consistent flow graph when producing or
 consuming profile data

Always try and merge "branch to next" blocks when building the intial flow graph
if BBINSTR or BBOPT is set.

Fixes #85856.
---
 src/coreclr/jit/compiler.h        | 9 +++++++--
 src/coreclr/jit/fgbasic.cpp       | 7 ++++---
 src/coreclr/jit/fgprofile.cpp     | 4 ++--
 src/coreclr/jit/importer.cpp      | 2 +-
 src/coreclr/jit/importercalls.cpp | 4 ++--
 5 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/coreclr/jit/compiler.h b/src/coreclr/jit/compiler.h
index 2e83e36b1dcba1..421bd023792db4 100644
--- a/src/coreclr/jit/compiler.h
+++ b/src/coreclr/jit/compiler.h
@@ -9464,9 +9464,14 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
             return jitFlags->IsSet(JitFlags::JIT_FLAG_BBINSTR);
         }
 
-        bool IsInstrumentedOptimized() const
+        bool IsInstrumentedAndOptimized() const
         {
-            return IsInstrumented() && jitFlags->IsSet(JitFlags::JIT_FLAG_TIER1);
+            return IsInstrumented() && jitFlags->IsSet(JitFlags::JIT_FLAG_BBOPT);
+        }
+
+        bool IsInstrumentedOrOptimized() const
+        {
+            return IsInstrumented() || jitFlags->IsSet(JitFlags::JIT_FLAG_BBOPT);
         }
 
         // true if we should use the PINVOKE_{BEGIN,END} helpers instead of generating
diff --git a/src/coreclr/jit/fgbasic.cpp b/src/coreclr/jit/fgbasic.cpp
index c5d780f7a36bca..cb627fd3b434be 100644
--- a/src/coreclr/jit/fgbasic.cpp
+++ b/src/coreclr/jit/fgbasic.cpp
@@ -1824,8 +1824,9 @@ void Compiler::fgFindJumpTargets(const BYTE* codeAddr, IL_OFFSET codeSize, Fixed
                 // Compute jump target address
                 signed jmpDist = (sz == 1) ? getI1LittleEndian(codeAddr) : getI4LittleEndian(codeAddr);
 
-                if (compIsForInlining() && jmpDist == 0 &&
-                    (opcode == CEE_LEAVE || opcode == CEE_LEAVE_S || opcode == CEE_BR || opcode == CEE_BR_S))
+                if ((jmpDist == 0) &&
+                    (opcode == CEE_LEAVE || opcode == CEE_LEAVE_S || opcode == CEE_BR || opcode == CEE_BR_S) &&
+                    opts.IsInstrumentedOrOptimized())
                 {
                     break; /* NOP */
                 }
@@ -2974,7 +2975,7 @@ unsigned Compiler::fgMakeBasicBlocks(const BYTE* codeAddr, IL_OFFSET codeSize, F
 
                 jmpDist = (sz == 1) ? getI1LittleEndian(codeAddr) : getI4LittleEndian(codeAddr);
 
-                if (compIsForInlining() && jmpDist == 0 && (opcode == CEE_BR || opcode == CEE_BR_S))
+                if ((jmpDist == 0) && (opcode == CEE_BR || opcode == CEE_BR_S) && opts.IsInstrumentedOrOptimized())
                 {
                     continue; /* NOP */
                 }
diff --git a/src/coreclr/jit/fgprofile.cpp b/src/coreclr/jit/fgprofile.cpp
index b391ae99dd4f09..ef614baca4815f 100644
--- a/src/coreclr/jit/fgprofile.cpp
+++ b/src/coreclr/jit/fgprofile.cpp
@@ -436,7 +436,7 @@ void BlockCountInstrumentor::RelocateProbes()
 {
     // We only see such blocks when optimizing. They are flagged by the importer.
     //
-    if (!m_comp->opts.IsInstrumentedOptimized() || ((m_comp->optMethodFlags & OMF_HAS_TAILCALL_SUCCESSOR) == 0))
+    if (!m_comp->opts.IsInstrumentedAndOptimized() || ((m_comp->optMethodFlags & OMF_HAS_TAILCALL_SUCCESSOR) == 0))
     {
         // No problematic blocks to worry about.
         //
@@ -1616,7 +1616,7 @@ void EfficientEdgeCountInstrumentor::RelocateProbes()
 {
     // We only see such blocks when optimizing. They are flagged by the importer.
     //
-    if (!m_comp->opts.IsInstrumentedOptimized() || ((m_comp->optMethodFlags & OMF_HAS_TAILCALL_SUCCESSOR) == 0))
+    if (!m_comp->opts.IsInstrumentedAndOptimized() || ((m_comp->optMethodFlags & OMF_HAS_TAILCALL_SUCCESSOR) == 0))
     {
         // No problematic blocks to worry about.
         //
diff --git a/src/coreclr/jit/importer.cpp b/src/coreclr/jit/importer.cpp
index 1c3fb163d19878..caa82b17b5011e 100644
--- a/src/coreclr/jit/importer.cpp
+++ b/src/coreclr/jit/importer.cpp
@@ -7476,7 +7476,7 @@ void Compiler::impImportBlockCode(BasicBlock* block)
             case CEE_BR_S:
                 jmpDist = (sz == 1) ? getI1LittleEndian(codeAddr) : getI4LittleEndian(codeAddr);
 
-                if (compIsForInlining() && jmpDist == 0)
+                if ((jmpDist == 0) && opts.IsInstrumentedOrOptimized())
                 {
                     break; /* NOP */
                 }
diff --git a/src/coreclr/jit/importercalls.cpp b/src/coreclr/jit/importercalls.cpp
index e80f210185c126..e9a1e4b21e7f64 100644
--- a/src/coreclr/jit/importercalls.cpp
+++ b/src/coreclr/jit/importercalls.cpp
@@ -1282,7 +1282,7 @@ var_types Compiler::impImportCall(OPCODE                  opcode,
         //    have to check for anything that might introduce a recursive tail call.
         // * We only instrument root method blocks in OSR methods,
         //
-        if ((opts.IsInstrumentedOptimized() || opts.IsOSR()) && !compIsForInlining())
+        if ((opts.IsInstrumentedAndOptimized() || opts.IsOSR()) && !compIsForInlining())
         {
             // If a root method tail call candidate block is not a BBJ_RETURN, it should have a unique
             // BBJ_RETURN successor. Mark that successor so we can handle it specially during profile
@@ -7201,7 +7201,7 @@ bool Compiler::impConsiderCallProbe(GenTreeCall* call, IL_OFFSET ilOffset)
         return false;
     }
 
-    assert(opts.OptimizationDisabled() || opts.IsInstrumentedOptimized());
+    assert(opts.OptimizationDisabled() || opts.IsInstrumentedAndOptimized());
     assert(!compIsForInlining());
 
     // During importation, optionally flag this block as one that