[llvm] [MIR] Allow overriding isSSA, noPhis, noVRegs in MIR input (PR #108546)

via llvm-commits llvm-commits at lists.llvm.org
Fri Sep 13 05:25:50 PDT 2024 

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-hexagon

Author: Dominik Montada (gargaroff)

<details>
<summary>Changes</summary>

Allow setting the computed properties IsSSA, NoPHIs, NoVRegs for MIR functions in MIR input. The default value is still the computed value. If the property is set to false, the computed result is ignored. This allows for tests where a pass is for example inserting PHI nodes into a function that didn't have any previously.

Closes #<!-- -->37787

---
Full diff: https://github.com/llvm/llvm-project/pull/108546.diff


11 Files Affected:

- (modified) llvm/include/llvm/CodeGen/MIRYamlMapping.h (+11) 
- (modified) llvm/lib/CodeGen/MIRParser/MIRParser.cpp (+13-6) 
- (modified) llvm/lib/CodeGen/MIRPrinter.cpp (+7) 
- (modified) llvm/test/CodeGen/AArch64/mlicm-stack-write-check.mir (+2-2) 
- (modified) llvm/test/CodeGen/AMDGPU/early-tailduplicator-nophis.mir (+3-1) 
- (modified) llvm/test/CodeGen/Hexagon/expand-condsets-impuse2.mir (+1-1) 
- (modified) llvm/test/CodeGen/Hexagon/expand-condsets-phys-reg.mir (+1-1) 
- (modified) llvm/test/CodeGen/Hexagon/expand-condsets-rm-reg.mir (+1-1) 
- (added) llvm/test/CodeGen/MIR/Generic/machine-function-optionally-computed-properties.mir (+42) 
- (modified) llvm/test/CodeGen/X86/sjlj-shadow-stack-liveness.mir (+1-2) 
- (modified) llvm/test/tools/llvm-reduce/mir/preserve-func-info.mir (+6) 


``````````diff
diff --git a/llvm/include/llvm/CodeGen/MIRYamlMapping.h b/llvm/include/llvm/CodeGen/MIRYamlMapping.h
index 304db57eca4994..e90c22284dcceb 100644
--- a/llvm/include/llvm/CodeGen/MIRYamlMapping.h
+++ b/llvm/include/llvm/CodeGen/MIRYamlMapping.h
@@ -730,6 +730,11 @@ struct MachineFunction {
   bool TracksRegLiveness = false;
   bool HasWinCFI = false;
 
+  // Computed properties that should be overridable
+  bool NoPHIs = false;
+  bool IsSSA = false;
+  bool NoVRegs = false;
+
   bool CallsEHReturn = false;
   bool CallsUnwindInit = false;
   bool HasEHCatchret = false;
@@ -770,6 +775,12 @@ template <> struct MappingTraits<MachineFunction> {
     YamlIO.mapOptional("tracksRegLiveness", MF.TracksRegLiveness, false);
     YamlIO.mapOptional("hasWinCFI", MF.HasWinCFI, false);
 
+    // PHIs must be not be capitalized, since it will clash with the MIR opcode
+    // leading to false-positive FileCheck hits with CHECK-NOT
+    YamlIO.mapOptional("noPhis", MF.NoPHIs, true);
+    YamlIO.mapOptional("isSSA", MF.IsSSA, true);
+    YamlIO.mapOptional("noVRegs", MF.NoVRegs, true);
+
     YamlIO.mapOptional("callsEHReturn", MF.CallsEHReturn, false);
     YamlIO.mapOptional("callsUnwindInit", MF.CallsUnwindInit, false);
     YamlIO.mapOptional("hasEHCatchret", MF.HasEHCatchret, false);
diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
index a5d6a40392d0cb..7d0876a33b70d4 100644
--- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -178,7 +178,8 @@ class MIRParserImpl {
   SMDiagnostic diagFromBlockStringDiag(const SMDiagnostic &Error,
                                        SMRange SourceRange);
 
-  void computeFunctionProperties(MachineFunction &MF);
+  void computeFunctionProperties(MachineFunction &MF,
+                                 const yaml::MachineFunction &YamlMF);
 
   void setupDebugValueTracking(MachineFunction &MF,
     PerFunctionMIParsingState &PFS, const yaml::MachineFunction &YamlMF);
@@ -373,7 +374,8 @@ static bool isSSA(const MachineFunction &MF) {
   return true;
 }
 
-void MIRParserImpl::computeFunctionProperties(MachineFunction &MF) {
+void MIRParserImpl::computeFunctionProperties(
+    MachineFunction &MF, const yaml::MachineFunction &YamlMF) {
   MachineFunctionProperties &Properties = MF.getProperties();
 
   bool HasPHI = false;
@@ -398,20 +400,25 @@ void MIRParserImpl::computeFunctionProperties(MachineFunction &MF) {
       }
     }
   }
-  if (!HasPHI)
+
+  // Don't overwrite NoPHIs if the input MIR explicitly set it to false
+  if (YamlMF.NoPHIs && !HasPHI)
     Properties.set(MachineFunctionProperties::Property::NoPHIs);
+
   MF.setHasInlineAsm(HasInlineAsm);
 
   if (HasTiedOps && AllTiedOpsRewritten)
     Properties.set(MachineFunctionProperties::Property::TiedOpsRewritten);
 
-  if (isSSA(MF))
+  // Don't overwrite IsSSA if the input MIR explicitly set it to false
+  if (YamlMF.IsSSA && isSSA(MF))
     Properties.set(MachineFunctionProperties::Property::IsSSA);
   else
     Properties.reset(MachineFunctionProperties::Property::IsSSA);
 
+  // Don't overwrite NoVRegs if the input MIR explicitly set it to false
   const MachineRegisterInfo &MRI = MF.getRegInfo();
-  if (MRI.getNumVirtRegs() == 0)
+  if (YamlMF.NoVRegs && MRI.getNumVirtRegs() == 0)
     Properties.set(MachineFunctionProperties::Property::NoVRegs);
 }
 
@@ -595,7 +602,7 @@ MIRParserImpl::initializeMachineFunction(const yaml::MachineFunction &YamlMF,
   MachineRegisterInfo &MRI = MF.getRegInfo();
   MRI.freezeReservedRegs();
 
-  computeFunctionProperties(MF);
+  computeFunctionProperties(MF, YamlMF);
 
   if (initializeCallSiteInfo(PFS, YamlMF))
     return false;
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 6e23969cd99bac..eb5259fd4b77ba 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -223,6 +223,13 @@ void MIRPrinter::print(const MachineFunction &MF) {
   YamlMF.TracksDebugUserValues = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::TracksDebugUserValues);
 
+  YamlMF.NoPHIs = MF.getProperties().hasProperty(
+      MachineFunctionProperties::Property::NoPHIs);
+  YamlMF.IsSSA = MF.getProperties().hasProperty(
+      MachineFunctionProperties::Property::IsSSA);
+  YamlMF.NoVRegs = MF.getProperties().hasProperty(
+      MachineFunctionProperties::Property::NoVRegs);
+
   convert(YamlMF, MF.getRegInfo(), MF.getSubtarget().getRegisterInfo());
   MachineModuleSlotTracker MST(MMI, &MF);
   MST.incorporateFunction(MF.getFunction());
diff --git a/llvm/test/CodeGen/AArch64/mlicm-stack-write-check.mir b/llvm/test/CodeGen/AArch64/mlicm-stack-write-check.mir
index 0b1fdf9c33d66c..b196d13deb74ac 100644
--- a/llvm/test/CodeGen/AArch64/mlicm-stack-write-check.mir
+++ b/llvm/test/CodeGen/AArch64/mlicm-stack-write-check.mir
@@ -2,6 +2,7 @@
 ---
 name: test
 tracksRegLiveness: true
+isSSA: false
 registers:
   - { id: 0, class: gpr64 }
 stack:
@@ -29,11 +30,11 @@ body: |
   bb.2:
     liveins: $x0
     %0 = COPY $x0
-    %0 = COPY $x0  ; Force isSSA = false.
 ...
 ---
 name: test2
 tracksRegLiveness: true
+isSSA: false
 registers:
   - { id: 0, class: gpr64 }
 stack:
@@ -61,5 +62,4 @@ body: |
   bb.2:
     liveins: $x0
     %0 = COPY $x0
-    %0 = COPY $x0  ; Force isSSA = false.
 ...
diff --git a/llvm/test/CodeGen/AMDGPU/early-tailduplicator-nophis.mir b/llvm/test/CodeGen/AMDGPU/early-tailduplicator-nophis.mir
index 2cb84c7ef4637d..9fcbdac0ff9d1f 100644
--- a/llvm/test/CodeGen/AMDGPU/early-tailduplicator-nophis.mir
+++ b/llvm/test/CodeGen/AMDGPU/early-tailduplicator-nophis.mir
@@ -2,11 +2,13 @@
 # RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -run-pass=early-tailduplication -verify-machineinstrs -o - %s | FileCheck %s
 
  # There are no phis in this testcase. Early tail duplication introduces them,
- # so the NoPHIs property needs to be cleared to avoid verifier errors
+ # so the NoPHIs property needs to be set explicitly to false to avoid verifier
+ # errors
 
 ---
 name:           tail_duplicate_nophis
 tracksRegLiveness: true
+noPhis: false
 body:             |
   ; CHECK-LABEL: name: tail_duplicate_nophis
   ; CHECK: bb.0:
diff --git a/llvm/test/CodeGen/Hexagon/expand-condsets-impuse2.mir b/llvm/test/CodeGen/Hexagon/expand-condsets-impuse2.mir
index ae3f4ba78cd1ff..ebb361ab433cb7 100644
--- a/llvm/test/CodeGen/Hexagon/expand-condsets-impuse2.mir
+++ b/llvm/test/CodeGen/Hexagon/expand-condsets-impuse2.mir
@@ -6,12 +6,12 @@
 
 name: f0
 tracksRegLiveness: true
+isSSA: false
 body: |
   bb.0:
     successors: %bb.1
     liveins: $r0, $r1
     %0:intregs = COPY $r0
-    %0:intregs = COPY $r0       ; defeat IsSSA detection
     %1:intregs = COPY $r1
     %2:intregs = COPY $r0
     %3:intregs = M2_mpyi %2, %1
diff --git a/llvm/test/CodeGen/Hexagon/expand-condsets-phys-reg.mir b/llvm/test/CodeGen/Hexagon/expand-condsets-phys-reg.mir
index e62cd1cc73609b..d252ec5fee4019 100644
--- a/llvm/test/CodeGen/Hexagon/expand-condsets-phys-reg.mir
+++ b/llvm/test/CodeGen/Hexagon/expand-condsets-phys-reg.mir
@@ -9,12 +9,12 @@
 
 name: fred
 tracksRegLiveness: true
+isSSA: false
 body: |
   bb.0:
     successors: %bb.1, %bb.2
     liveins: $r0
 
-    %0:intregs = A2_tfrsi 0           ;; Multiple defs to ensure IsSSA = false
     %0:intregs = L2_loadri_io $r0, 0
     %1:predregs = C2_cmpgti %0, 10
     %2:intregs = C2_mux %1, $r31, %0
diff --git a/llvm/test/CodeGen/Hexagon/expand-condsets-rm-reg.mir b/llvm/test/CodeGen/Hexagon/expand-condsets-rm-reg.mir
index 6d7b6cd72a3099..463aa9a8e7f9b1 100644
--- a/llvm/test/CodeGen/Hexagon/expand-condsets-rm-reg.mir
+++ b/llvm/test/CodeGen/Hexagon/expand-condsets-rm-reg.mir
@@ -20,6 +20,7 @@
 
 name: fred
 tracksRegLiveness: true
+isSSA: false
 registers:
   - { id: 0, class: intregs }
   - { id: 1, class: intregs }
@@ -35,7 +36,6 @@ body: |
   bb.0:
     liveins: $r0, $r1, $p0
         %0 = COPY $r0
-        %0 = COPY $r0  ; Force isSSA = false.
         %1 = COPY $r1
         %2 = COPY $p0
         ; Check that %3 was coalesced into %4.
diff --git a/llvm/test/CodeGen/MIR/Generic/machine-function-optionally-computed-properties.mir b/llvm/test/CodeGen/MIR/Generic/machine-function-optionally-computed-properties.mir
new file mode 100644
index 00000000000000..c833e380480021
--- /dev/null
+++ b/llvm/test/CodeGen/MIR/Generic/machine-function-optionally-computed-properties.mir
@@ -0,0 +1,42 @@
+# RUN: llc -run-pass none -o - %s | FileCheck %s
+# Test that we can disable certain properties that are normally computed
+
+---
+# CHECK-LABEL: name: TestNoPhis
+# CHECK: noPhis: true
+# CHECK: ...
+name:            TestNoPhis
+...
+---
+# CHECK-LABEL: name: TestNoPhisOverride
+# CHECK: noPhis: false
+# CHECK: ...
+name:            TestNoPhisOverride
+noPhis: false
+...
+---
+# CHECK-LABEL: name: TestIsSSA
+# CHECK: isSSA: true
+# CHECK: ...
+name:            TestIsSSA
+...
+---
+# CHECK-LABEL: name: TestIsSSAOverride
+# CHECK: isSSA: false
+# CHECK: ...
+name:            TestIsSSAOverride
+isSSA: false
+...
+---
+# CHECK-LABEL: name: TestNoVRegs
+# CHECK: noVRegs: true
+# CHECK: ...
+name:            TestNoVRegs
+...
+---
+# CHECK-LABEL: name: TestNoVRegsOverride
+# CHECK: noVRegs: false
+# CHECK: ...
+name:            TestNoVRegsOverride
+noVRegs: false
+...
diff --git a/llvm/test/CodeGen/X86/sjlj-shadow-stack-liveness.mir b/llvm/test/CodeGen/X86/sjlj-shadow-stack-liveness.mir
index 3def36f9d8ba91..83bc8ec510f646 100644
--- a/llvm/test/CodeGen/X86/sjlj-shadow-stack-liveness.mir
+++ b/llvm/test/CodeGen/X86/sjlj-shadow-stack-liveness.mir
@@ -14,6 +14,7 @@ name:            bar
 # CHECK-LABEL: name: bar
 alignment:       16
 tracksRegLiveness: true
+noPhis: false
 body:             |
   bb.0:
     %0:gr64 = IMPLICIT_DEF
@@ -29,8 +30,6 @@ body:             |
     ; CHECK-NOT: MOV64rm killed %0
     ; CHECK-NEXT: MOV64rm killed %0
 
-  ; FIXME: Dummy PHI to set the property NoPHIs to false. PR38439.
   bb.2:
-    %1:gr64 = PHI undef %1, %bb.2, undef %1, %bb.2
     JMP_1 %bb.2
 ...
diff --git a/llvm/test/tools/llvm-reduce/mir/preserve-func-info.mir b/llvm/test/tools/llvm-reduce/mir/preserve-func-info.mir
index 5f11cea89d7e7b..f735dfd5cbbf01 100644
--- a/llvm/test/tools/llvm-reduce/mir/preserve-func-info.mir
+++ b/llvm/test/tools/llvm-reduce/mir/preserve-func-info.mir
@@ -14,6 +14,9 @@
 # RESULT-NEXT: failedISel:      true
 # RESULT-NEXT: tracksRegLiveness: true
 # RESULT-NEXT: hasWinCFI:       true
+# RESULT-NEXT: noPhis:          false
+# RESULT-NEXT: isSSA:           false
+# RESULT-NEXT: noVRegs:         false
 # RESULT-NEXT: callsEHReturn: true
 # RESULT-NEXT: callsUnwindInit: true
 # RESULT-NEXT: hasEHCatchret: true
@@ -41,6 +44,9 @@ selected:        true
 failedISel:      true
 tracksRegLiveness: true
 hasWinCFI:       true
+noPhis:          false
+isSSA:           false
+noVRegs:         false
 failsVerification: true
 tracksDebugUserValues: true
 callsEHReturn: true

``````````

</details>


https://github.com/llvm/llvm-project/pull/108546

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