[PATCH] D47921: [ARM] Allow CMPZ transforms even if the input has multiple uses.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added a reviewer: SjoerdMeijer.
Herald added a reviewer: javed.absar.
Herald added subscribers: chrib, kristof.beyls.

It looks like this got left in by accident in r289794; I can't think of any reason the check would be necessary.  (Maybe it was meant to be a check that the AND has one use? But we check that a few lines earlier.)


Repository:
  rL LLVM

https://reviews.llvm.org/D47921

Files:
  lib/Target/ARM/ARMISelDAGToDAG.cpp
  test/CodeGen/ARM/and-cmpz.ll
  test/CodeGen/ARM/load_i1_select.ll
  test/CodeGen/Thumb/thumb-shrink-wrapping.ll


Index: test/CodeGen/Thumb/thumb-shrink-wrapping.ll
===================================================================
--- test/CodeGen/Thumb/thumb-shrink-wrapping.ll
+++ test/CodeGen/Thumb/thumb-shrink-wrapping.ll
@@ -646,12 +646,12 @@
 ; CHECK-NEXT: beq [[EXIT_LABEL:LBB[0-9_]+]]
 ; ENABLE: push {r4, lr}
 
-; CHECK: tst r3, r4
+; CHECK: lsls    r4, r3, #30
 ; ENABLE-NEXT: ldr [[POP:r[4567]]], [sp, #4]
 ; ENABLE-NEXT: mov lr, [[POP]]
 ; ENABLE-NEXT: pop {[[POP]]}
 ; ENABLE-NEXT: add sp, #4
-; CHECK-NEXT: beq [[EXIT_LABEL]]
+; CHECK-NEXT: bpl [[EXIT_LABEL]]
 
 ; CHECK: str r1, [r2]
 ; CHECK: str r3, [r2]
Index: test/CodeGen/ARM/load_i1_select.ll
===================================================================
--- test/CodeGen/ARM/load_i1_select.ll
+++ test/CodeGen/ARM/load_i1_select.ll
@@ -8,7 +8,7 @@
 
 ; CHECK-LABEL: foo:
 ; CHECK: ldrb r[[R0:[0-9]+]], [r0]
-; CHECK: tst.w r[[R0]], #1
+; CHECK: lsls r{{[0-9]+}}, r[[R0]], #31
 define void @foo(i8* %call, double* %p) nounwind {
 entry:
   %tmp2 = load i8, i8* %call
Index: test/CodeGen/ARM/and-cmpz.ll
===================================================================
--- test/CodeGen/ARM/and-cmpz.ll
+++ test/CodeGen/ARM/and-cmpz.ll
@@ -18,6 +18,24 @@
   ret i32 2
 }
 
+; CHECK-LABEL: single_bit_multi_use:
+; CHECK: lsls r0, r0, #23
+; T2-NEXT: mov
+; T2-NEXT: it
+; T1-NEXT: bmi
+define i32 @single_bit_multi_use(i32 %p, i32* %z) {
+  store i32 %p, i32* %z
+  %a = and i32 %p, 256
+  %b = icmp eq i32 %a, 0
+  br i1 %b, label %true, label %false
+
+true:
+  ret i32 1
+
+false:
+  ret i32 2
+}
+
 ; CHECK-LABEL: multi_bit_lsb_ubfx:
 ; CHECK: lsls r0, r0, #24
 ; T2-NEXT: mov
Index: lib/Target/ARM/ARMISelDAGToDAG.cpp
===================================================================
--- lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -2459,7 +2459,7 @@
   SDValue X = And.getOperand(0);
   auto C = dyn_cast<ConstantSDNode>(And.getOperand(1));
 
-  if (!C || !X->hasOneUse())
+  if (!C)
     return;
   auto Range = getContiguousRangeOfSetBits(C->getAPIntValue());
   if (!Range)


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