[llvm-mca] Correctly update the rank in `Scheduler::select()`.

Found by inspection.

llvm-svn: 338579

2 files changed, 115 insertions, 1 deletions

diff --git a/llvm/test/tools/llvm-mca/X86/BtVer2/rank.s b/llvm/test/tools/llvm-mca/X86/BtVer2/rank.s
new file mode 100644
index 00000000000..f83961e0799
--- /dev/null
+++ b/llvm/test/tools/llvm-mca/X86/BtVer2/rank.s
@@ -0,0 +1,112 @@
+# NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
+# RUN: llvm-mca -mtriple=x86_64-unknown-unknown -mcpu=btver2 -timeline -timeline-max-iterations=3 < %s | FileCheck %s
+
+add %eax, %ecx
+add %eax, %edx
+add %eax, %ebx
+add %edx, %esi
+add %ebx, %eax
+add %edx, %esi
+add %ebx, %eax
+add %ebx, %eax
+
+# CHECK:      Iterations:        100
+# CHECK-NEXT: Instructions:      800
+# CHECK-NEXT: Total Cycles:      503
+# CHECK-NEXT: Dispatch Width:    2
+# CHECK-NEXT: IPC:               1.59
+# CHECK-NEXT: Block RThroughput: 4.0
+
+# CHECK:      Instruction Info:
+# CHECK-NEXT: [1]: #uOps
+# CHECK-NEXT: [2]: Latency
+# CHECK-NEXT: [3]: RThroughput
+# CHECK-NEXT: [4]: MayLoad
+# CHECK-NEXT: [5]: MayStore
+# CHECK-NEXT: [6]: HasSideEffects (U)
+
+# CHECK:      [1]    [2]    [3]    [4]    [5]    [6]    Instructions:
+# CHECK-NEXT:  1      1     0.50                        addl	%eax, %ecx
+# CHECK-NEXT:  1      1     0.50                        addl	%eax, %edx
+# CHECK-NEXT:  1      1     0.50                        addl	%eax, %ebx
+# CHECK-NEXT:  1      1     0.50                        addl	%edx, %esi
+# CHECK-NEXT:  1      1     0.50                        addl	%ebx, %eax
+# CHECK-NEXT:  1      1     0.50                        addl	%edx, %esi
+# CHECK-NEXT:  1      1     0.50                        addl	%ebx, %eax
+# CHECK-NEXT:  1      1     0.50                        addl	%ebx, %eax
+
+# CHECK:      Resources:
+# CHECK-NEXT: [0]   - JALU0
+# CHECK-NEXT: [1]   - JALU1
+# CHECK-NEXT: [2]   - JDiv
+# CHECK-NEXT: [3]   - JFPA
+# CHECK-NEXT: [4]   - JFPM
+# CHECK-NEXT: [5]   - JFPU0
+# CHECK-NEXT: [6]   - JFPU1
+# CHECK-NEXT: [7]   - JLAGU
+# CHECK-NEXT: [8]   - JMul
+# CHECK-NEXT: [9]   - JSAGU
+# CHECK-NEXT: [10]  - JSTC
+# CHECK-NEXT: [11]  - JVALU0
+# CHECK-NEXT: [12]  - JVALU1
+# CHECK-NEXT: [13]  - JVIMUL
+
+# CHECK:      Resource pressure per iteration:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]
+# CHECK-NEXT: 4.00   4.00    -      -      -      -      -      -      -      -      -      -      -      -
+
+# CHECK:      Resource pressure by instruction:
+# CHECK-NEXT: [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]    [10]   [11]   [12]   [13]   Instructions:
+# CHECK-NEXT: 0.02   0.98    -      -      -      -      -      -      -      -      -      -      -      -     addl	%eax, %ecx
+# CHECK-NEXT: 0.02   0.98    -      -      -      -      -      -      -      -      -      -      -      -     addl	%eax, %edx
+# CHECK-NEXT: 0.96   0.04    -      -      -      -      -      -      -      -      -      -      -      -     addl	%eax, %ebx
+# CHECK-NEXT: 1.00    -      -      -      -      -      -      -      -      -      -      -      -      -     addl	%edx, %esi
+# CHECK-NEXT:  -     1.00    -      -      -      -      -      -      -      -      -      -      -      -     addl	%ebx, %eax
+# CHECK-NEXT: 1.00    -      -      -      -      -      -      -      -      -      -      -      -      -     addl	%edx, %esi
+# CHECK-NEXT:  -     1.00    -      -      -      -      -      -      -      -      -      -      -      -     addl	%ebx, %eax
+# CHECK-NEXT: 1.00    -      -      -      -      -      -      -      -      -      -      -      -      -     addl	%ebx, %eax
+
+# CHECK:      Timeline view:
+# CHECK-NEXT:                     01234567
+# CHECK-NEXT: Index     0123456789
+
+# CHECK:      [0,0]     DeER .    .    . .   addl	%eax, %ecx
+# CHECK-NEXT: [0,1]     DeER .    .    . .   addl	%eax, %edx
+# CHECK-NEXT: [0,2]     .DeER.    .    . .   addl	%eax, %ebx
+# CHECK-NEXT: [0,3]     .DeER.    .    . .   addl	%edx, %esi
+# CHECK-NEXT: [0,4]     . DeER    .    . .   addl	%ebx, %eax
+# CHECK-NEXT: [0,5]     . DeER    .    . .   addl	%edx, %esi
+# CHECK-NEXT: [0,6]     .  DeER   .    . .   addl	%ebx, %eax
+# CHECK-NEXT: [0,7]     .  D=eER  .    . .   addl	%ebx, %eax
+# CHECK-NEXT: [1,0]     .   D=eER .    . .   addl	%eax, %ecx
+# CHECK-NEXT: [1,1]     .   D=eER .    . .   addl	%eax, %edx
+# CHECK-NEXT: [1,2]     .    D=eER.    . .   addl	%eax, %ebx
+# CHECK-NEXT: [1,3]     .    D=eER.    . .   addl	%edx, %esi
+# CHECK-NEXT: [1,4]     .    .D=eER    . .   addl	%ebx, %eax
+# CHECK-NEXT: [1,5]     .    .D=eER    . .   addl	%edx, %esi
+# CHECK-NEXT: [1,6]     .    . D=eER   . .   addl	%ebx, %eax
+# CHECK-NEXT: [1,7]     .    . D==eER  . .   addl	%ebx, %eax
+# CHECK-NEXT: [2,0]     .    .  D==eER . .   addl	%eax, %ecx
+# CHECK-NEXT: [2,1]     .    .  D==eER . .   addl	%eax, %edx
+# CHECK-NEXT: [2,2]     .    .   D==eER. .   addl	%eax, %ebx
+# CHECK-NEXT: [2,3]     .    .   D==eER. .   addl	%edx, %esi
+# CHECK-NEXT: [2,4]     .    .    D==eER .   addl	%ebx, %eax
+# CHECK-NEXT: [2,5]     .    .    D==eER .   addl	%edx, %esi
+# CHECK-NEXT: [2,6]     .    .    .D==eER.   addl	%ebx, %eax
+# CHECK-NEXT: [2,7]     .    .    .D===eER   addl	%ebx, %eax
+
+# CHECK:      Average Wait times (based on the timeline view):
+# CHECK-NEXT: [0]: Executions
+# CHECK-NEXT: [1]: Average time spent waiting in a scheduler's queue
+# CHECK-NEXT: [2]: Average time spent waiting in a scheduler's queue while ready
+# CHECK-NEXT: [3]: Average time elapsed from WB until retire stage
+
+# CHECK:            [0]    [1]    [2]    [3]
+# CHECK-NEXT: 0.     3     2.0    0.3    0.0       addl	%eax, %ecx
+# CHECK-NEXT: 1.     3     2.0    0.3    0.0       addl	%eax, %edx
+# CHECK-NEXT: 2.     3     2.0    1.0    0.0       addl	%eax, %ebx
+# CHECK-NEXT: 3.     3     2.0    0.0    0.0       addl	%edx, %esi
+# CHECK-NEXT: 4.     3     2.0    0.0    0.0       addl	%ebx, %eax
+# CHECK-NEXT: 5.     3     2.0    0.0    0.0       addl	%edx, %esi
+# CHECK-NEXT: 6.     3     2.0    0.0    0.0       addl	%ebx, %eax
+# CHECK-NEXT: 7.     3     3.0    0.0    0.0       addl	%ebx, %eax
diff --git a/llvm/tools/llvm-mca/Scheduler.cpp b/llvm/tools/llvm-mca/Scheduler.cpp
index 975a50e4b63..b98fab87b3a 100644
--- a/llvm/tools/llvm-mca/Scheduler.cpp
+++ b/llvm/tools/llvm-mca/Scheduler.cpp
@@ -333,8 +333,10 @@ InstRef Scheduler::select() {
     int CurrentRank = I->first - I->second->getNumUsers();
     if (CurrentRank < Rank) {
       const InstrDesc &D = I->second->getDesc();
-      if (Resources->canBeIssued(D))
+      if (Resources->canBeIssued(D)) {
+        Rank = CurrentRank;
         It = I;
+      }
     }
   }