[PATCH] D138454: GlobalISel: Enable CSE of G_SELECT

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: aemerson, paquette, Pierre-vh.
Herald added subscribers: kosarev, kerbowa, hiraditya, jvesely.
Herald added a project: All.
arsenm requested review of this revision.
Herald added a subscriber: wdng.
Herald added a project: LLVM.

Stop trying to delete a select in one combine since it would
be deleting the CSE'd instruction if that happened.


https://reviews.llvm.org/D138454

Files:
  llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
  llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
  llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fold-binop-into-select.mir


Index: llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fold-binop-into-select.mir
===================================================================
--- llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fold-binop-into-select.mir
+++ llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fold-binop-into-select.mir
@@ -938,8 +938,8 @@
     ; CHECK-NEXT: %cond:_(s1) = G_ICMP intpred(eq), %reg(s32), %zero
     ; CHECK-NEXT: %ten:_(s32) = G_CONSTANT i32 10
     ; CHECK-NEXT: %twenty:_(s32) = G_CONSTANT i32 20
-    ; CHECK-NEXT: %smin:_(s32) = G_SELECT %cond(s1), %ten, %twenty
-    ; CHECK-NEXT: S_ENDPGM 0, implicit %smin(s32)
+    ; CHECK-NEXT: %select:_(s32) = G_SELECT %cond(s1), %ten, %twenty
+    ; CHECK-NEXT: S_ENDPGM 0, implicit %select(s32)
     %reg:_(s32) = COPY $vgpr0
     %zero:_(s32) = G_CONSTANT i32 0
     %cond:_(s1) = G_ICMP intpred(eq), %reg, %zero
@@ -987,8 +987,8 @@
     ; CHECK-NEXT: %cond:_(s1) = G_ICMP intpred(eq), %reg(s32), %zero
     ; CHECK-NEXT: %ten:_(s32) = G_CONSTANT i32 10
     ; CHECK-NEXT: %twenty:_(s32) = G_CONSTANT i32 20
-    ; CHECK-NEXT: %umin:_(s32) = G_SELECT %cond(s1), %ten, %twenty
-    ; CHECK-NEXT: S_ENDPGM 0, implicit %umin(s32)
+    ; CHECK-NEXT: %select:_(s32) = G_SELECT %cond(s1), %ten, %twenty
+    ; CHECK-NEXT: S_ENDPGM 0, implicit %select(s32)
     %reg:_(s32) = COPY $vgpr0
     %zero:_(s32) = G_CONSTANT i32 0
     %cond:_(s1) = G_ICMP intpred(eq), %reg, %zero
Index: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -3196,8 +3196,6 @@
   }
 
   Builder.buildSelect(Dst, SelectCond, FoldTrue, FoldFalse, MI.getFlags());
-  Observer.erasingInstr(*Select);
-  Select->eraseFromParent();
   MI.eraseFromParent();
 
   return true;
Index: llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
+++ llvm/lib/CodeGen/GlobalISel/CSEInfo.cpp
@@ -61,6 +61,7 @@
   case TargetOpcode::G_TRUNC:
   case TargetOpcode::G_PTR_ADD:
   case TargetOpcode::G_EXTRACT:
+  case TargetOpcode::G_SELECT:
     return true;
   }
   return false;


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