[llvm] 4c5909b - [SampleFDO] Add two passes of MIRAddFSDiscriminatorsPass

[Rong Xu via llvm-commits]

Author: Rong Xu
Date: 2021-08-11T11:11:04-07:00
New Revision: 4c5909ba83036ed74f2ddd76f69b3b1bf15bd5f1

URL: https://github.com/llvm/llvm-project/commit/4c5909ba83036ed74f2ddd76f69b3b1bf15bd5f1
DIFF: https://github.com/llvm/llvm-project/commit/4c5909ba83036ed74f2ddd76f69b3b1bf15bd5f1.diff

LOG: [SampleFDO] Add two passes of MIRAddFSDiscriminatorsPass

This patch adds Pass1 of MIRADDFSDiscriminatorsPass before register
allocation, and Pass2 of MIRAddFSDiscriminatorsPass before
Block-Placement. This is still under --enable-fs-discrmininator
option (default false).

This would reduce the turn-around time for FSAFDO transition.

Differential Revision: https://reviews.llvm.org/D104579

Added: 
    

Modified: 
    llvm/lib/CodeGen/TargetPassConfig.cpp
    llvm/test/CodeGen/X86/fsafdo_test1.ll
    llvm/test/CodeGen/X86/fsafdo_test2.ll

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 4024fd452fc45..c31deceb9ae35 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -1113,6 +1113,12 @@ void TargetPassConfig::addMachinePasses() {
   // where it becomes safe again so stop debugifying here.
   DebugifyIsSafe = false;
 
+  // Add a FSDiscriminator pass right before RA, so that we could get
+  // more precise SampleFDO profile for RA.
+  if (EnableFSDiscriminator)
+    addPass(createMIRAddFSDiscriminatorsPass(
+        sampleprof::FSDiscriminatorPass::Pass1));
+
   // Run register allocation and passes that are tightly coupled with it,
   // including phi elimination and scheduling.
   if (getOptimizeRegAlloc())
@@ -1465,6 +1471,9 @@ bool TargetPassConfig::addGCPasses() {
 
 /// Add standard basic block placement passes.
 void TargetPassConfig::addBlockPlacement() {
+  if (EnableFSDiscriminator)
+    addPass(createMIRAddFSDiscriminatorsPass(
+        sampleprof::FSDiscriminatorPass::Pass2));
   if (addPass(&MachineBlockPlacementID)) {
     // Run a separate pass to collect block placement statistics.
     if (EnableBlockPlacementStats)

diff  --git a/llvm/test/CodeGen/X86/fsafdo_test1.ll b/llvm/test/CodeGen/X86/fsafdo_test1.ll
index 99c65c917f69e..ca7120461481b 100644
--- a/llvm/test/CodeGen/X86/fsafdo_test1.ll
+++ b/llvm/test/CodeGen/X86/fsafdo_test1.ll
@@ -3,8 +3,8 @@
 ; Check that fs-afdo discriminators are generated.
 ; CHECK: .loc    1 7 3 is_stmt 0 discriminator 2 # foo.c:7:3
 ; Check: .loc    1 9 5 is_stmt 1 discriminator 2 # foo.c:9:5
-; CHECK: .loc    1 9 5 is_stmt 0 discriminator 268435458 # foo.c:9:5
-; CHECK: .loc    1 7 3 is_stmt 1 discriminator 3892314114 # foo.c:7:3
+; CHECK: .loc    1 9 5 is_stmt 0 discriminator 11266 # foo.c:9:5
+; CHECK: .loc    1 7 3 is_stmt 1 discriminator 11266 # foo.c:7:3
 ; Check that variable __llvm_fs_discriminator__ is generated.
 ; CHECK: .type   __llvm_fs_discriminator__, at object # @__llvm_fs_discriminator__
 ; CHECK: .section        .rodata,"a", at progbits

diff  --git a/llvm/test/CodeGen/X86/fsafdo_test2.ll b/llvm/test/CodeGen/X86/fsafdo_test2.ll
index ca26f307b08be..7695f3e373dc6 100644
--- a/llvm/test/CodeGen/X86/fsafdo_test2.ll
+++ b/llvm/test/CodeGen/X86/fsafdo_test2.ll
@@ -38,9 +38,9 @@
 ;;
 ;; Check that fs-afdo discriminators are generated.
 ; CHECK: .loc    1 23 9 is_stmt 0 discriminator 1 # unroll.c:23:9
-; CHECK: .loc    1 23 9 is_stmt 0 discriminator 3892314113 # unroll.c:23:9
-; CHECK: .loc    1 23 9 is_stmt 0 discriminator 2818572289 # unroll.c:23:9
-; CHECK: .loc    1 23 9 is_stmt 0 discriminator 3623878657 # unroll.c:23:9
+; CHECK: .loc    1 23 9 is_stmt 0 discriminator 3585 # unroll.c:23:9
+; CHECK: .loc    1 23 9 is_stmt 0 discriminator 8705 # unroll.c:23:9
+; CHECK: .loc    1 23 9 is_stmt 0 discriminator 4097 # unroll.c:23:9
 ;;
 ;; Check that variable __llvm_fs_discriminator__ is generated.
 ; CHECK: .type   __llvm_fs_discriminator__, at object # @__llvm_fs_discriminator__