[llvm] [AMDGPU] RewriteMFMAFormStage: single exit copy for same-block uses (PR #209179)

[Romanov Vlad via llvm-commits]

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@@ -0,0 +1,84 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 6
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx950 -run-pass=machine-scheduler -amdgpu-disable-rewrite-mfma-form-sched-stage=false %s -o - | FileCheck %s
+
+# Test that only one copy generated for all users of mfma in the same block.
+
+--- |
+  define void @mfma_no_multiple_copies() #0 { ret void }
+  attributes #0 = { "amdgpu-waves-per-eu"="1,1" "amdgpu-flat-work-group-size"="64,64" }
+...
+
+---
+name: mfma_no_multiple_copies
+tracksRegLiveness: true
+machineFunctionInfo:
+  isEntryFunction: true
+body: |
+  ; CHECK-LABEL: name: mfma_no_multiple_copies
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x80000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   %p0:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %m3:vreg_128_align2 = IMPLICIT_DEF
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:areg_128_align2 = COPY %m3
+  ; CHECK-NEXT:   %p1:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p2:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p3:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p4:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p5:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p6:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   %p7:vreg_1024 = IMPLICIT_DEF
+  ; CHECK-NEXT:   S_BRANCH %bb.1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1:
+  ; CHECK-NEXT:   successors: %bb.1(0x7c000000), %bb.2(0x04000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   %m0:areg_128_align2 = V_MFMA_F32_16X16X32_F16_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, [[COPY]], 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   %m1:areg_128_align2 = V_MFMA_F32_16X16X32_F16_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m0, 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   %m2:areg_128_align2 = V_MFMA_F32_16X16X32_F16_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m1, 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   S_CBRANCH_SCC1 %bb.2, implicit undef $scc
+  ; CHECK-NEXT:   S_BRANCH %bb.1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2:
+  ; CHECK-NEXT:   KILL %p0, %p1, %p2, %p3, %p4, %p5, %p6, %p7
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:areg_128_align2 = V_MFMA_F32_16X16X32_F16_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m2, 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:vreg_128_align2 = COPY [[COPY]]
+  ; CHECK-NEXT:   %out1:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, [[COPY1]], 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   %out2:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s1:vreg_128_align2, undef %s0:vreg_128_align2, [[COPY1]], 0, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   S_ENDPGM 0, implicit %out1, implicit %out2
+  bb.0:
+    successors: %bb.1(0x80000000)
+    %p0:vreg_1024 = IMPLICIT_DEF
+    %p1:vreg_1024 = IMPLICIT_DEF
+    %p2:vreg_1024 = IMPLICIT_DEF
+    %p3:vreg_1024 = IMPLICIT_DEF
+    %p4:vreg_1024 = IMPLICIT_DEF
+    %p5:vreg_1024 = IMPLICIT_DEF
+    %p6:vreg_1024 = IMPLICIT_DEF
+    %p7:vreg_1024 = IMPLICIT_DEF
+
+    %m3:vreg_128_align2 = IMPLICIT_DEF
+
+    S_BRANCH %bb.1
+
+  bb.1:
+    successors: %bb.1(0x7c000000), %bb.2(0x04000000)
+
+    %m0:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m3, 0, 0, 0, implicit $mode, implicit $exec
+    %m1:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m0, 0, 0, 0, implicit $mode, implicit $exec
+    %m2:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m1, 0, 0, 0, implicit $mode, implicit $exec
+
+    S_CBRANCH_SCC1 %bb.2, implicit undef $scc
+    S_BRANCH %bb.1
+
+  bb.2:
+
+    %m3:vreg_128_align2 = V_MFMA_F32_16X16X32_F16_vgprcd_e64 undef %s0:vreg_128_align2, undef %s1:vreg_128_align2, %m2, 0, 0, 0, implicit $mode, implicit $exec
----------------
romanovvlad wrote:

Done.

https://github.com/llvm/llvm-project/pull/209179