[llvm] r305290 - [MIPS] BuildCondBr should preserve MO flags
Simon Dardis via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 13 07:11:29 PDT 2017
Author: sdardis
Date: Tue Jun 13 09:11:29 2017
New Revision: 305290
URL: http://llvm.org/viewvc/llvm-project?rev=305290&view=rev
Log:
[MIPS] BuildCondBr should preserve MO flags
While simplifying branches in the MachineInstr representation, the
routine BuildCondBr must preserve flags on register MachineOperands. In
particular, it must preserve the <undef> flag.
This fixes a bug that is unlikely to occur in any real scenario, but
which bugpoint is likely to introduce.
Patch By Nick Johnson!
Reviewers: ahatanak, sdardis
Differential Revision: https://reviews.llvm.org/D34041
Added:
llvm/trunk/test/CodeGen/Mips/brundef.ll
Modified:
llvm/trunk/lib/Target/Mips/MipsInstrInfo.cpp
Modified: llvm/trunk/lib/Target/Mips/MipsInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsInstrInfo.cpp?rev=305290&r1=305289&r2=305290&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MipsInstrInfo.cpp Tue Jun 13 09:11:29 2017
@@ -103,12 +103,9 @@ void MipsInstrInfo::BuildCondBr(MachineB
MachineInstrBuilder MIB = BuildMI(&MBB, DL, MCID);
for (unsigned i = 1; i < Cond.size(); ++i) {
- if (Cond[i].isReg())
- MIB.addReg(Cond[i].getReg());
- else if (Cond[i].isImm())
- MIB.addImm(Cond[i].getImm());
- else
- assert(false && "Cannot copy operand");
+ assert((Cond[i].isImm() || Cond[i].isReg()) &&
+ "Cannot copy operand for conditional branch!");
+ MIB.add(Cond[i]);
}
MIB.addMBB(TBB);
}
Added: llvm/trunk/test/CodeGen/Mips/brundef.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/brundef.ll?rev=305290&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/brundef.ll (added)
+++ llvm/trunk/test/CodeGen/Mips/brundef.ll Tue Jun 13 09:11:29 2017
@@ -0,0 +1,26 @@
+; RUN: llc -march=mips -mcpu=mips32 -verify-machineinstrs -o /dev/null < %s
+; Confirm that MachineInstr branch simplification preserves
+; register operand flags, such as the <undef> flag.
+
+define void @ham() {
+bb:
+ %tmp = alloca i32, align 4
+ %tmp13 = ptrtoint i32* %tmp to i32
+ %tmp70 = icmp eq i32 undef, -1
+ br i1 %tmp70, label %bb72, label %bb40
+
+bb72: ; preds = %bb72, %bb
+ br i1 undef, label %bb40, label %bb72
+
+bb40: ; preds = %bb72, %bb
+ %tmp41 = phi i32 [ %tmp13, %bb72 ], [ %tmp13, %bb ]
+ %tmp55 = inttoptr i32 %tmp41 to i32*
+ %tmp58 = insertelement <2 x i32*> undef, i32* %tmp55, i32 1
+ br label %bb59
+
+bb59: ; preds = %bb59, %bb40
+ %tmp60 = phi <2 x i32*> [ %tmp61, %bb59 ], [ %tmp58, %bb40 ]
+ %tmp61 = getelementptr i32, <2 x i32*> %tmp60, <2 x i32> <i32 -1, i32 1>
+ %tmp62 = extractelement <2 x i32*> %tmp61, i32 1
+ br label %bb59
+}
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