Delete dead PHI machine instructions. These can be created due to type
legalization even when the IR-level optimizer has removed dead phis, such
as when the high half of an i64 value is unused on a 32-bit target.
I had to adjust a few test cases that had dead phis.
This is a partial fix for Radar 7627077.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95816 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp
index b0cb24d..6e01e59 100644
--- a/lib/CodeGen/DeadMachineInstructionElim.cpp
+++ b/lib/CodeGen/DeadMachineInstructionElim.cpp
@@ -55,7 +55,7 @@
bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const {
// Don't delete instructions with side effects.
bool SawStore = false;
- if (!MI->isSafeToMove(TII, SawStore, 0))
+ if (!MI->isSafeToMove(TII, SawStore, 0) && !MI->isPHI())
return false;
// Examine each operand.
diff --git a/test/CodeGen/ARM/remat.ll b/test/CodeGen/ARM/remat.ll
index 367f782..92c1cf1 100644
--- a/test/CodeGen/ARM/remat.ll
+++ b/test/CodeGen/ARM/remat.ll
@@ -32,16 +32,16 @@
br label %phi1.exit
phi1.exit: ; preds = %bb.i35, %bb142
- %.pn = phi double [ %6, %bb.i35 ], [ 0.000000e+00, %bb142 ] ; <double> [#uses=0]
+ %.pn = phi double [ %6, %bb.i35 ], [ 0.000000e+00, %bb142 ] ; <double> [#uses=1]
%9 = phi double [ %8, %bb.i35 ], [ 0.000000e+00, %bb142 ] ; <double> [#uses=1]
- %10 = fmul double undef, %9 ; <double> [#uses=0]
+ %10 = fmul double %.pn, %9 ; <double> [#uses=1]
br i1 %14, label %phi0.exit, label %bb.i
bb.i: ; preds = %phi1.exit
unreachable
phi0.exit: ; preds = %phi1.exit
- %11 = fsub double %4, undef ; <double> [#uses=1]
+ %11 = fsub double %4, %10 ; <double> [#uses=1]
%12 = fadd double 0.000000e+00, %11 ; <double> [#uses=1]
store double %12, double* undef, align 4
br label %bb142
diff --git a/test/CodeGen/X86/2007-10-05-3AddrConvert.ll b/test/CodeGen/X86/2007-10-05-3AddrConvert.ll
index 67323e8..2c2706d 100644
--- a/test/CodeGen/X86/2007-10-05-3AddrConvert.ll
+++ b/test/CodeGen/X86/2007-10-05-3AddrConvert.ll
@@ -36,7 +36,9 @@
bb107.i.i: ; preds = %bb107.i.i, %bb.i6.i
%q_addr.0.i.i.in = phi %struct.bnode** [ null, %bb107.i.i ], [ %4, %bb.i6.i ] ; <%struct.bnode**> [#uses=1]
- %q_addr.0.i.i = load %struct.bnode** %q_addr.0.i.i.in ; <%struct.bnode*> [#uses=0]
+ %q_addr.0.i.i = load %struct.bnode** %q_addr.0.i.i.in ; <%struct.bnode*> [#uses=1]
+ %q_addr.1 = getelementptr %struct.anon* %0, i32 0, i32 4, i32 1
+ store %struct.bnode* %q_addr.0.i.i, %struct.bnode** %q_addr.1, align 4
br label %bb107.i.i
bb47.loopexit.i: ; preds = %bb32.i