[PATCH] D118621: [AArch64] Make machine combiner patterns preserve MIFlags

[John Brawn via Phabricator via llvm-commits]

john.brawn created this revision.
john.brawn added reviewers: fhahn, dmgreen, kpn, t.p.northover.
Herald added subscribers: hiraditya, kristof.beyls.
john.brawn requested review of this revision.
Herald added a project: LLVM.

This is mainly done so that we don't lose the nofpexcept flag once we start emitting it.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118621

Files:
  llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
  llvm/test/CodeGen/AArch64/machine-combiner-instr-fmf.mir


Index: llvm/test/CodeGen/AArch64/machine-combiner-instr-fmf.mir
===================================================================
--- llvm/test/CodeGen/AArch64/machine-combiner-instr-fmf.mir
+++ llvm/test/CodeGen/AArch64/machine-combiner-instr-fmf.mir
@@ -6,7 +6,7 @@
 # CHECK:        [[C:%.*]]:fpr32 = COPY $s2
 # CHECK-NEXT:   [[B:%.*]]:fpr32 = COPY $s1
 # CHECK-NEXT:   [[A:%.*]]:fpr32 = COPY $s0
-# CHECK-NEXT:   :fpr32 = FMADDSrrr [[B]], [[A]], [[C]]
+# CHECK-NEXT:   :fpr32 = nnan ninf nsz arcp contract afn reassoc FMADDSrrr [[B]], [[A]], [[C]]
 ---
 name:            scalar_fmadd_fast
 alignment:       4
@@ -45,7 +45,7 @@
 # CHECK:        [[C:%.*]]:fpr32 = COPY $s2
 # CHECK-NEXT:   [[B:%.*]]:fpr32 = COPY $s1
 # CHECK-NEXT:   [[A:%.*]]:fpr32 = COPY $s0
-# CHECK-NEXT:   :fpr32 = FMADDSrrr [[B]], [[A]], [[C]]
+# CHECK-NEXT:   :fpr32 = contract FMADDSrrr [[B]], [[A]], [[C]]
 
 ---
 name:            scalar_fmadd_contract
@@ -125,7 +125,7 @@
 # CHECK:        [[C:%.*]]:fpr32 = COPY $s2
 # CHECK-NEXT:   [[B:%.*]]:fpr32 = COPY $s1
 # CHECK-NEXT:   [[A:%.*]]:fpr32 = COPY $s0
-# CHECK-NEXT:   :fpr32 = FMADDSrrr [[B]], [[A]], [[C]]
+# CHECK-NEXT:   :fpr32 = contract FMADDSrrr [[B]], [[A]], [[C]]
 
 ---
 name:            scalar_fmadd_contract_op1
@@ -206,7 +206,7 @@
 # CHECK:       [[C:%.*]]:fpr128 = COPY $q2
 # CHECK-NEXT:  [[B:%.*]]:fpr128 = COPY $q1
 # CHECK-NEXT:  [[A:%.*]]:fpr128 = COPY $q0
-# CHECK-NEXT:  fpr128 = FMLAv2f64 [[C]], [[B]], [[A]]
+# CHECK-NEXT:  fpr128 = nnan ninf nsz arcp contract afn reassoc FMLAv2f64 [[C]], [[B]], [[A]]
 ---
 name:            vector_fmadd_fast
 alignment:       4
@@ -245,7 +245,7 @@
 # CHECK:       [[C:%.*]]:fpr128 = COPY $q2
 # CHECK-NEXT:  [[B:%.*]]:fpr128 = COPY $q1
 # CHECK-NEXT:  [[A:%.*]]:fpr128 = COPY $q0
-# CHECK-NEXT:  fpr128 = FMLAv2f64 [[C]], [[B]], [[A]]
+# CHECK-NEXT:  fpr128 = contract FMLAv2f64 [[C]], [[B]], [[A]]
 ---
 name:            vector_fmadd_contract
 alignment:       4
@@ -324,7 +324,7 @@
 # CHECK:       [[C:%.*]]:fpr128 = COPY $q2
 # CHECK-NEXT:  [[B:%.*]]:fpr128 = COPY $q1
 # CHECK-NEXT:  [[A:%.*]]:fpr128 = COPY $q0
-# CHECK-NEXT:  fpr128 = FMLAv2f64 [[C]], [[B]], [[A]]
+# CHECK-NEXT:  fpr128 = contract FMLAv2f64 [[C]], [[B]], [[A]]
 
 ---
 name:            vector_fmadd_contract_op1
Index: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -6225,6 +6225,14 @@
   if (MUL)
     DelInstrs.push_back(MUL);
   DelInstrs.push_back(&Root);
+
+  // Set the flags on the inserted instructions to be the merged flags of the
+  // instructions that we have combined.
+  uint16_t Flags = Root.getFlags();
+  if (MUL)
+    Flags = Root.mergeFlagsWith(*MUL);
+  for (auto *MI : InsInstrs)
+    MI->setFlags(Flags);
 }
 
 /// Replace csincr-branch sequence by simple conditional branch


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D118621.404555.patch
Type: text/x-patch
Size: 2931 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220131/7440c0e1/attachment.bin>