[GlobalISel] Partially revert r371901.

r371901 was overeager and widenScalarDst() and the like in the legalizer
attempt to increment the insert point given in order to add new instructions
after the currently legalizing inst. In cases where the insertion point is not
exactly the current instruction, then callers need to de-compensate for the
behaviour by decrementing the insertion iterator before calling them. It's not
a nice state of affairs, for now just undo the problematic parts of the change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372050 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 8c356c62a17654819b203521e37f97b96ec21345..d4ae3b52a465c1fdc5567b2add33098470629477 100644 (file)
--- a/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1765,7 +1765,7 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
     }
 
     MachineBasicBlock &MBB = *MI.getParent();
-    MIRBuilder.setInsertPt(MBB, MBB.getFirstNonPHI());
+    MIRBuilder.setInsertPt(MBB, --MBB.getFirstNonPHI());
     widenScalarDst(MI, WideTy);
     Observer.changedInstr(MI);
     return Legalized;
@@ -3156,7 +3156,7 @@ LegalizerHelper::moreElementsVectorPhi(MachineInstr &MI, unsigned TypeIdx,
   }
 
   MachineBasicBlock &MBB = *MI.getParent();
-  MIRBuilder.setInsertPt(MBB, MBB.getFirstNonPHI());
+  MIRBuilder.setInsertPt(MBB, --MBB.getFirstNonPHI());
   moreElementsVectorDst(MI, MoreTy, 0);
   Observer.changedInstr(MI);
   return Legalized;

diff --git a/test/CodeGen/AArch64/GlobalISel/legalize-phi-insertpt-decrement.mir b/test/CodeGen/AArch64/GlobalISel/legalize-phi-insertpt-decrement.mir
new file mode 100644 (file)
index 0000000..87db607
--- /dev/null
+++ b/test/CodeGen/AArch64/GlobalISel/legalize-phi-insertpt-decrement.mir
@@ -0,0 +1,99 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -O0 -mtriple=aarch64-unknown-unknown -verify-machineinstrs -run-pass=legalizer %s -o - | FileCheck %s
+--- |
+  target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+  define void @snork() {
+  bb:
+    br label %bb1
+
+  bb1:                                              ; preds = %bb3, %bb
+    %lsr.iv = phi i16* [ %scevgep, %bb3 ], [ undef, %bb ]
+    %tmp = phi i1 [ %tmp9, %bb3 ], [ undef, %bb ]
+    br i1 %tmp, label %bb10, label %bb3
+
+  bb3:                                              ; preds = %bb1
+    %tmp5 = getelementptr i16, i16* null, i64 2
+    %tmp6 = load i16, i16* %lsr.iv, align 2, !tbaa !0
+    %tmp7 = icmp eq i16 %tmp6, -1
+    %tmp8 = load i16, i16* %tmp5, align 2, !tbaa !0
+    %tmp9 = icmp eq i16 %tmp8, -1
+    %scevgep = getelementptr i16, i16* %lsr.iv, i64 2
+    br i1 %tmp7, label %bb10, label %bb1
+
+  bb10:                                             ; preds = %bb3, %bb1
+    ret void
+  }
+
+  !0 = !{!1, !1, i64 0}
+  !1 = !{!"short", !2, i64 0}
+  !2 = !{!"omnipotent char", !3, i64 0}
+  !3 = !{!"Simple C/C++ TBAA"}
+
+...
+---
+name:            snork
+alignment:       16
+tracksRegLiveness: true
+frameInfo:
+  maxAlignment:    1
+body:             |
+  ; CHECK-LABEL: name: snork
+  ; CHECK: bb.0.bb:
+  ; CHECK:   successors: %bb.1(0x80000000)
+  ; CHECK:   [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 0
+  ; CHECK:   [[INTTOPTR:%[0-9]+]]:_(p0) = G_INTTOPTR [[C]](s64)
+  ; CHECK:   [[DEF:%[0-9]+]]:_(p0) = G_IMPLICIT_DEF
+  ; CHECK:   [[DEF1:%[0-9]+]]:_(s16) = G_IMPLICIT_DEF
+  ; CHECK: bb.1.bb1:
+  ; CHECK:   successors: %bb.3(0x40000000), %bb.2(0x40000000)
+  ; CHECK:   [[PHI:%[0-9]+]]:_(p0) = G_PHI %6(p0), %bb.2, [[DEF]](p0), %bb.0
+  ; CHECK:   [[PHI1:%[0-9]+]]:_(s16) = G_PHI %20(s16), %bb.2, [[DEF1]](s16), %bb.0
+  ; CHECK:   [[TRUNC:%[0-9]+]]:_(s1) = G_TRUNC [[PHI1]](s16)
+  ; CHECK:   G_BRCOND [[TRUNC]](s1), %bb.3
+  ; CHECK: bb.2.bb3:
+  ; CHECK:   successors: %bb.3(0x40000000), %bb.1(0x40000000)
+  ; CHECK:   [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 4
+  ; CHECK:   [[GEP:%[0-9]+]]:_(p0) = G_GEP [[INTTOPTR]], [[C1]](s64)
+  ; CHECK:   [[LOAD:%[0-9]+]]:_(s16) = G_LOAD [[PHI]](p0) :: (load 2 from %ir.lsr.iv)
+  ; CHECK:   [[ZEXT:%[0-9]+]]:_(s32) = G_ZEXT [[LOAD]](s16)
+  ; CHECK:   [[C2:%[0-9]+]]:_(s32) = G_CONSTANT i32 65535
+  ; CHECK:   [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[ZEXT]](s32), [[C2]]
+  ; CHECK:   [[TRUNC1:%[0-9]+]]:_(s1) = G_TRUNC [[ICMP]](s32)
+  ; CHECK:   [[LOAD1:%[0-9]+]]:_(s16) = G_LOAD [[GEP]](p0) :: (load 2 from %ir.tmp5)
+  ; CHECK:   [[ZEXT1:%[0-9]+]]:_(s32) = G_ZEXT [[LOAD1]](s16)
+  ; CHECK:   [[COPY:%[0-9]+]]:_(s32) = COPY [[C2]](s32)
+  ; CHECK:   [[ICMP1:%[0-9]+]]:_(s32) = G_ICMP intpred(eq), [[ZEXT1]](s32), [[COPY]]
+  ; CHECK:   [[GEP1:%[0-9]+]]:_(p0) = G_GEP [[PHI]], [[C1]](s64)
+  ; CHECK:   [[TRUNC2:%[0-9]+]]:_(s16) = G_TRUNC [[ICMP1]](s32)
+  ; CHECK:   G_BRCOND [[TRUNC1]](s1), %bb.3
+  ; CHECK:   G_BR %bb.1
+  ; CHECK: bb.3.bb10:
+  ; CHECK:   RET 0
+  bb.1.bb:
+    %3:_(s64) = G_CONSTANT i64 0
+    %2:_(p0) = G_INTTOPTR %3(s64)
+    %7:_(s16) = G_CONSTANT i16 -1
+    %12:_(p0) = G_IMPLICIT_DEF
+    %13:_(s1) = G_IMPLICIT_DEF
+
+  bb.2.bb1:
+    %0:_(p0) = G_PHI %11(p0), %bb.3, %12(p0), %bb.1
+    %1:_(s1) = G_PHI %10(s1), %bb.3, %13(s1), %bb.1
+    G_BRCOND %1(s1), %bb.4
+
+  bb.3.bb3:
+    %4:_(s64) = G_CONSTANT i64 4
+    %5:_(p0) = G_GEP %2, %4(s64)
+    %6:_(s16) = G_LOAD %0(p0) :: (load 2 from %ir.lsr.iv)
+    %8:_(s1) = G_ICMP intpred(eq), %6(s16), %7
+    %9:_(s16) = G_LOAD %5(p0) :: (load 2 from %ir.tmp5)
+    %10:_(s1) = G_ICMP intpred(eq), %9(s16), %7
+    %11:_(p0) = G_GEP %0, %4(s64)
+    G_BRCOND %8(s1), %bb.4
+    G_BR %bb.2
+
+  bb.4.bb10:
+    RET 0
+
+...

diff --git a/test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir b/test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
index 24b144c376a4a48bbe0ae5d372713434013ae095..f17323cdd3f5ad52d1b6f158f375456b7131f1e5 100644 (file)
--- a/test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
+++ b/test/CodeGen/AMDGPU/GlobalISel/legalize-phi.mir
@@ -160,8 +160,8 @@ body: |
   ; CHECK:   G_BR %bb.2
   ; CHECK: bb.2:
   ; CHECK:   [[PHI:%[0-9]+]]:_(<4 x s16>) = G_PHI [[INSERT]](<4 x s16>), %bb.0, [[INSERT3]](<4 x s16>), %bb.1
-  ; CHECK:   [[DEF4:%[0-9]+]]:_(<4 x s16>) = G_IMPLICIT_DEF
   ; CHECK:   [[EXTRACT1:%[0-9]+]]:_(<3 x s16>) = G_EXTRACT [[PHI]](<4 x s16>), 0
+  ; CHECK:   [[DEF4:%[0-9]+]]:_(<4 x s16>) = G_IMPLICIT_DEF
   ; CHECK:   [[INSERT4:%[0-9]+]]:_(<4 x s16>) = G_INSERT [[DEF4]], [[EXTRACT1]](<3 x s16>), 0
   ; CHECK:   $vgpr0_vgpr1 = COPY [[INSERT4]](<4 x s16>)
   ; CHECK:   S_SETPC_B64 undef $sgpr30_sgpr31