[llvm] d53b3df - [InstCombine] Remove unneeded isa<PHINode> check in foldOpIntoPhi

[Dhruv Chawla via llvm-commits]

Author: Dhruv Chawla
Date: 2023-08-16T21:09:08+05:30
New Revision: d53b3df570e359d175d6e7a825ad1a02f9bc80a3

URL: https://github.com/llvm/llvm-project/commit/d53b3df570e359d175d6e7a825ad1a02f9bc80a3
DIFF: https://github.com/llvm/llvm-project/commit/d53b3df570e359d175d6e7a825ad1a02f9bc80a3.diff

LOG: [InstCombine] Remove unneeded isa<PHINode> check in foldOpIntoPhi

This check is redundant as it is covered by the call to
isPotentiallyReachable.

Depends on D155726.

Differential Revision: https://reviews.llvm.org/D155718

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
    llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
    llvm/test/Transforms/InstCombine/icmp-fold-into-phi.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 2722160e72c149..111e2de4722f01 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1396,7 +1396,6 @@ Instruction *InstCombinerImpl::foldOpIntoPhi(Instruction &I, PHINode *PN) {
       continue;
     }
 
-    if (isa<PHINode>(InVal)) return nullptr;  // Itself a phi.
     if (NonSimplifiedBB) return nullptr;  // More than one non-simplified value.
 
     NonSimplifiedBB = InBB;

diff  --git a/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
index 64a6e033e88fa7..0fa8a74d250d25 100644
--- a/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
+++ b/llvm/test/Analysis/ValueTracking/known-power-of-two-urem.ll
@@ -15,12 +15,11 @@ define i64 @known_power_of_two_urem_phi(i64 %size, i1 %cmp, i1 %cmp1) {
 ; CHECK:       cond.true.false:
 ; CHECK-NEXT:    br label [[COND_TRUE_END]]
 ; CHECK:       cond.true.end:
-; CHECK-NEXT:    [[PHI:%.*]] = phi i64 [ 2, [[COND_TRUE_TRUE]] ], [ 4, [[COND_TRUE_FALSE]] ]
+; CHECK-NEXT:    [[PHI:%.*]] = phi i64 [ 1, [[COND_TRUE_TRUE]] ], [ 3, [[COND_TRUE_FALSE]] ]
 ; CHECK-NEXT:    br label [[COND_END]]
 ; CHECK:       cond.end:
-; CHECK-NEXT:    [[PHI1:%.*]] = phi i64 [ 4096, [[ENTRY:%.*]] ], [ [[PHI]], [[COND_TRUE_END]] ]
-; CHECK-NEXT:    [[TMP0:%.*]] = add nsw i64 [[PHI1]], -1
-; CHECK-NEXT:    [[UREM:%.*]] = and i64 [[TMP0]], [[SIZE:%.*]]
+; CHECK-NEXT:    [[PHI1:%.*]] = phi i64 [ 4095, [[ENTRY:%.*]] ], [ [[PHI]], [[COND_TRUE_END]] ]
+; CHECK-NEXT:    [[UREM:%.*]] = and i64 [[PHI1]], [[SIZE:%.*]]
 ; CHECK-NEXT:    ret i64 [[UREM]]
 ;
 entry:

diff  --git a/llvm/test/Transforms/InstCombine/icmp-fold-into-phi.ll b/llvm/test/Transforms/InstCombine/icmp-fold-into-phi.ll
index ebefb31c4874dd..3d7177859e3f5b 100644
--- a/llvm/test/Transforms/InstCombine/icmp-fold-into-phi.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-fold-into-phi.ll
@@ -10,14 +10,14 @@ define i1 @SwitchTest(i32 %x, i32 %y) {
 ; CHECK-NEXT:    i32 1, label [[BB3:%.*]]
 ; CHECK-NEXT:    ]
 ; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp ugt i32 [[Y]], 1
 ; CHECK-NEXT:    br label [[BB2]]
 ; CHECK:       bb2:
-; CHECK-NEXT:    [[PHI1:%.*]] = phi i32 [ 1, [[ENTRY:%.*]] ], [ [[Y]], [[BB1]] ]
+; CHECK-NEXT:    [[PHI1:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[TMP0]], [[BB1]] ]
 ; CHECK-NEXT:    br label [[BB3]]
 ; CHECK:       bb3:
-; CHECK-NEXT:    [[PHI2:%.*]] = phi i32 [ [[PHI1]], [[BB2]] ], [ 0, [[ENTRY]] ]
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[PHI2]], 1
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    [[PHI2:%.*]] = phi i1 [ [[PHI1]], [[BB2]] ], [ false, [[ENTRY]] ]
+; CHECK-NEXT:    ret i1 [[PHI2]]
 ;
 entry:
   switch i32 %x, label %bb1 [