[PATCH] D70699: [CriticalAntiDepBreaker] Teach the regmask clobber check to check if any subregister is preserved before considering the super register clobbered

[Craig Topper via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG9283681e1681: [CriticalAntiDepBreaker] Teach the regmask clobber check to check if any… (authored by craig.topper).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D70699/new/

https://reviews.llvm.org/D70699

Files:
  llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
  llvm/test/CodeGen/X86/pr44140.ll


Index: llvm/test/CodeGen/X86/pr44140.ll
===================================================================
--- llvm/test/CodeGen/X86/pr44140.ll
+++ llvm/test/CodeGen/X86/pr44140.ll
@@ -10,7 +10,6 @@
 
 ; We need xmm6 to be live from the loop header across all iterations of the loop.
 ; We shouldn't clobber ymm6 inside the loop.
-; FIXME: We currently clobber ymm6
 define i32 @main() {
 ; CHECK-LABEL: main:
 ; CHECK:       # %bb.0: # %start
@@ -23,7 +22,7 @@
 ; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm0
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm1
-; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm6
+; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm7
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm2
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm3
 ; CHECK-NEXT:    vmovups %ymm0, {{[0-9]+}}(%rsp)
@@ -31,10 +30,10 @@
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm1
 ; CHECK-NEXT:    vmovups %ymm3, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups %ymm2, {{[0-9]+}}(%rsp)
-; CHECK-NEXT:    vmovups %ymm6, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    vmovups %ymm7, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups %ymm3, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups %ymm2, {{[0-9]+}}(%rsp)
-; CHECK-NEXT:    vmovups %ymm6, {{[0-9]+}}(%rsp)
+; CHECK-NEXT:    vmovups %ymm7, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups %ymm1, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups %ymm1, {{[0-9]+}}(%rsp)
 ; CHECK-NEXT:    vmovups {{[0-9]+}}(%rsp), %ymm5
Index: llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
===================================================================
--- llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
+++ llvm/lib/CodeGen/CriticalAntiDepBreaker.cpp
@@ -261,15 +261,25 @@
     for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
       MachineOperand &MO = MI.getOperand(i);
 
-      if (MO.isRegMask())
-        for (unsigned i = 0, e = TRI->getNumRegs(); i != e; ++i)
-          if (MO.clobbersPhysReg(i)) {
+      if (MO.isRegMask()) {
+        auto ClobbersPhysRegAndSubRegs = [&](unsigned PhysReg) {
+          for (MCSubRegIterator SRI(PhysReg, TRI, true); SRI.isValid(); ++SRI)
+            if (!MO.clobbersPhysReg(*SRI))
+              return false;
+
+          return true;
+        };
+
+        for (unsigned i = 0, e = TRI->getNumRegs(); i != e; ++i) {
+          if (ClobbersPhysRegAndSubRegs(i)) {
             DefIndices[i] = Count;
             KillIndices[i] = ~0u;
             KeepRegs.reset(i);
             Classes[i] = nullptr;
             RegRefs.erase(i);
           }
+        }
+      }
 
       if (!MO.isReg()) continue;
       Register Reg = MO.getReg();


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