[AMDGPU] Add test for v_fmamk_f16/v_fmaak_f16 in real-true16. NFC

[rampitec]

This is to display a bug in real true16 mode that we do not have
an allocatable 16-bit VGPR class and these instructions do not
have VOP3 forms for allocatable VGPR_16 to be used. To use these
instructions 'VGPR_16_Lo128' must be allocable.

[rampitec]

• [AMDGPU] Allow 16-bit imm folding in real true16 #173318
• [AMDGPU] Create V_FMAAK_F16/V_FMAMK_F16 in true16 with imm folding #173317
• [AMDGPU] Make VGPR_16_Lo128 allocatable #173309
• [AMDGPU] Add test for v_fmamk_f16/v_fmaak_f16 in real-true16. NFC #173307 👈
• main

This stack of pull requests is managed by sgh.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Stanislav Mekhanoshin (rampitec)

Changes

This is to display a bug in real true16 mode that we do not have
an allocatable 16-bit VGPR class and these instructions do not
have VOP3 forms for allocatable VGPR_16 to be used. To use these
instructions 'VGPR_16_Lo128' must be allocable.

---

Full diff: https://github.com/llvm/llvm-project/pull/173307.diff

1 Files Affected:

• (added) llvm/test/CodeGen/AMDGPU/fmamk_fmaak-t16.mir (+31)

diff --git a/llvm/test/CodeGen/AMDGPU/fmamk_fmaak-t16.mir b/llvm/test/CodeGen/AMDGPU/fmamk_fmaak-t16.mir
new file mode 100644
index 0000000000000..75aa62b63e832
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/fmamk_fmaak-t16.mir
@@ -0,0 +1,31 @@
+# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -run-pass=machineverifier -filetype=null %s 2>&1 | FileCheck %s -check-prefix=GFX11
+# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -start-before=greedy,0 -stop-after=virtregrewriter,2 -o - %s 2>&1 | FileCheck %s -check-prefix=GFX11
+
+# FIXME: There is no allocatable 16-bit VGPR class and these instructions
+#        do not have VOP3 forms for allocatable VGPR_16 to be used.
+
+# GFX11: Cannot use non-allocatable class 'VGPR_16_Lo128' for virtual register
+
+---
+name:            v_fmamk_f16
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+    %0:vgpr_32_lo128 = COPY $vgpr0
+    %1:vgpr_32_lo128 = COPY $vgpr1
+    %2:vgpr_16_lo128 = nofpexcept V_FMAMK_F16_t16 %0.sub0, 1, %1.sub1, implicit $exec, implicit $mode
+    S_ENDPGM 0, implicit %2
+...
+
+---
+name:            v_fmaak_f16
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+    %0:vgpr_32_lo128 = COPY $vgpr0
+    %1:vgpr_32_lo128 = COPY $vgpr1
+    %2:vgpr_16_lo128 = nofpexcept V_FMAAK_F16_t16 %0.sub0, %1.sub1, 1, implicit $exec, implicit $mode
+    S_ENDPGM 0, implicit %2
+...

[arsenm]

Suggested change

	# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -run-pass=machineverifier -filetype=null %s 2>&1 | FileCheck %s -check-prefix=GFX11
	# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -start-before=greedy,0 -stop-after=virtregrewriter,2 -o - %s 2>&1 | FileCheck %s -check-prefix=GFX11
	# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -run-pass=none -filetype=null %s 2>&1 | FileCheck -check-prefix=GFX11 %s
	# RUN: not llc -mtriple=amdgcn -mcpu=gfx1100 -mattr=+real-true16 -start-before=greedy,0 -stop-after=virtregrewriter,2 -o - %s 2>&1 | FileCheck -check-prefix=GFX11 %s

[arsenm]

I'm not sure what the point of the second run line is, the error seems to come from the MIR parser (instead of the machine verifier, for some reason)?

Test also belongs in test/MachineVerifier or CodeGen/MIR