[MISched] Fix post-RA pickOnlyChoice debug logs

[tomershafir]

On the way, adding a stable test for pickOnlyChoice() scheduling paths directly, which has been missing, while filechecking the fixed tracing.

[llvmorg-github-actions]

@llvm/pr-subscribers-backend-aarch64

Author: Tomer Shafir (tomershafir)

Changes

On the way, adding a stable test for pickOnlyOnce() scheduling paths directly, which has been missing, while filechecking the fixed tracing.

---

Full diff: https://github.com/llvm/llvm-project/pull/222927.diff

2 Files Affected:

• (modified) llvm/lib/CodeGen/MachineScheduler.cpp (+1-1)
• (added) llvm/test/CodeGen/AArch64/misched-postra-only1.mir (+114)

diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index 4438adfaec2c1..1afbc6a789bb4 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -4532,7 +4532,7 @@ SUnit *PostGenericScheduler::pickNode(bool &IsTopNode) {
   if (RegionPolicy.OnlyBottomUp) {
     SU = Bot.pickOnlyChoice();
     if (SU) {
-      tracePick(SU, Only1, /*IsTopNode=*/true, /*IsPostRA=*/true);
+      tracePick(SU, Only1, /*IsTopNode=*/false, /*IsPostRA=*/true);
     } else {
       CandPolicy NoPolicy;
       BotCand.reset(NoPolicy);
diff --git a/llvm/test/CodeGen/AArch64/misched-postra-only1.mir b/llvm/test/CodeGen/AArch64/misched-postra-only1.mir
new file mode 100644
index 0000000000000..c3f61537dd596
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/misched-postra-only1.mir
@@ -0,0 +1,114 @@
+# REQUIRES: asserts
+
+# RUN: llc -mtriple=aarch64 -mcpu=apple-m5 -run-pass=postmisched \
+# RUN:   -enable-post-misched -verify-machineinstrs \
+# RUN:   -debug-only=machine-scheduler -misched-postra-direction=topdown \
+# RUN:   -o - %s 2>&1 | FileCheck --check-prefix=TOPDOWN %s
+# RUN: llc -mtriple=aarch64 -mcpu=apple-m5 -run-pass=postmisched \
+# RUN:   -enable-post-misched -verify-machineinstrs \
+# RUN:   -debug-only=machine-scheduler -misched-postra-direction=bottomup \
+# RUN:   -o - %s 2>&1 | FileCheck --check-prefix=BOTTOMUP %s
+# RUN: llc -mtriple=aarch64 -mcpu=apple-m5 -run-pass=postmisched \
+# RUN:   -enable-post-misched -verify-machineinstrs \
+# RUN:   -debug-only=machine-scheduler -misched-postra-direction=bidirectional \
+# RUN:   -o - %s 2>&1 | FileCheck --check-prefix=BIDIR %s
+
+---
+# A linear dependency chain leaves exactly one node available in either zone at
+# every step, so every pick comes from pickOnlyChoice(). Bidirectional picks
+# bottom-up throughout, because the bottom zone is queried first.
+
+# TOPDOWN:      chain:%bb.0
+# TOPDOWN:      Pick Top Cand SU(0) ONLY1      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(0)
+# TOPDOWN:      Pick Top Cand SU(1) ONLY1      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(1)
+# TOPDOWN:      Pick Top Cand SU(2) ONLY1      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(2)
+# TOPDOWN:      *** Final schedule for %bb.0 ***
+# TOPDOWN-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# TOPDOWN-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+# TOPDOWN-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x2, 1, 0
+
+# BOTTOMUP:      chain:%bb.0
+# BOTTOMUP:      Pick Bot Cand SU(2) ONLY1      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(2)
+# BOTTOMUP:      Pick Bot Cand SU(1) ONLY1      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(1)
+# BOTTOMUP:      Pick Bot Cand SU(0) ONLY1      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(0)
+# BOTTOMUP:      *** Final schedule for %bb.0 ***
+# BOTTOMUP-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# BOTTOMUP-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+# BOTTOMUP-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x2, 1, 0
+
+# BIDIR:      chain:%bb.0
+# BIDIR:      Pick Bot Cand SU(2) ONLY1      [post-RA]
+# BIDIR-NEXT: Scheduling SU(2)
+# BIDIR:      Pick Bot Cand SU(1) ONLY1      [post-RA]
+# BIDIR-NEXT: Scheduling SU(1)
+# BIDIR:      Pick Bot Cand SU(0) ONLY1      [post-RA]
+# BIDIR-NEXT: Scheduling SU(0)
+# BIDIR:      *** Final schedule for %bb.0 ***
+# BIDIR-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# BIDIR-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+# BIDIR-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x2, 1, 0
+name:            chain
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0
+    renamable $x1 = ADDXri renamable $x0, 1, 0
+    renamable $x2 = ADDXri renamable $x1, 1, 0
+    renamable $x3 = ADDXri renamable $x2, 1, 0
+    RET_ReallyLR implicit $x3
+...
+---
+# A fan-out leaves two nodes available at the bottom but only one at the top,
+# so bidirectional scheduling falls through to Top.pickOnlyChoice().
+
+# TOPDOWN:      fanout:%bb.0
+# TOPDOWN:      Pick Top Cand SU(0) ONLY1      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(0)
+# TOPDOWN:      Pick Top Cand SU(1) ORDER      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(1)
+# TOPDOWN:      Pick Top Cand SU(2) ONLY1      [post-RA]
+# TOPDOWN-NEXT: Scheduling SU(2)
+# TOPDOWN:      *** Final schedule for %bb.0 ***
+# TOPDOWN-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# TOPDOWN-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+# TOPDOWN-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x1, 2, 0
+
+# BOTTOMUP:      fanout:%bb.0
+# BOTTOMUP:      Pick Bot Cand SU(1) ORDER      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(1)
+# BOTTOMUP:      Pick Bot Cand SU(2) ONLY1      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(2)
+# BOTTOMUP:      Pick Bot Cand SU(0) ONLY1      [post-RA]
+# BOTTOMUP-NEXT: Scheduling SU(0)
+# BOTTOMUP:      *** Final schedule for %bb.0 ***
+# BOTTOMUP-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# BOTTOMUP-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x1, 2, 0
+# BOTTOMUP-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+
+# BIDIR:      fanout:%bb.0
+# BIDIR:      Pick Top Cand SU(0) ONLY1      [post-RA]
+# BIDIR-NEXT: Scheduling SU(0)
+# BIDIR:      Pick Bot Cand SU(1) ORDER      [post-RA]
+# BIDIR-NEXT: Scheduling SU(1)
+# BIDIR:      Pick Bot Cand SU(2) ONLY1      [post-RA]
+# BIDIR-NEXT: Scheduling SU(2)
+# BIDIR:      *** Final schedule for %bb.0 ***
+# BIDIR-NEXT: SU(0):   renamable $x1 = ADDXri renamable $x0, 1, 0
+# BIDIR-NEXT: SU(2):   renamable $x3 = ADDXri renamable $x1, 2, 0
+# BIDIR-NEXT: SU(1):   renamable $x2 = ADDXri renamable $x1, 1, 0
+name:            fanout
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $x0
+    renamable $x1 = ADDXri renamable $x0, 1, 0
+    renamable $x2 = ADDXri renamable $x1, 1, 0
+    renamable $x3 = ADDXri renamable $x1, 2, 0
+    RET_ReallyLR implicit $x2, implicit $x3
+...