[llvm-commits] [llvm] r101162 - in /llvm/trunk: lib/Target/X86/X86InstrInfo.cpp test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll test/CodeGen/X86/brcond.ll
Evan Cheng
evan.cheng at apple.com
Tue Apr 13 11:50:27 PDT 2010
Author: evancheng
Date: Tue Apr 13 13:50:27 2010
New Revision: 101162
URL: http://llvm.org/viewvc/llvm-project?rev=101162&view=rev
Log:
Re-apply 101075 and fix it properly. Just reuse the debug info of the branch instruction being optimized. There is no need to --I which can deref off start of the BB.
Added:
llvm/trunk/test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll
Modified:
llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
llvm/trunk/test/CodeGen/X86/brcond.ll
Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.cpp?rev=101162&r1=101161&r2=101162&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86InstrInfo.cpp Tue Apr 13 13:50:27 2010
@@ -1684,6 +1684,7 @@
// Start from the bottom of the block and work up, examining the
// terminator instructions.
MachineBasicBlock::iterator I = MBB.end();
+ MachineBasicBlock::iterator UnCondBrIter = MBB.end();
while (I != MBB.begin()) {
--I;
if (I->isDebugValue())
@@ -1701,6 +1702,8 @@
// Handle unconditional branches.
if (I->getOpcode() == X86::JMP_4) {
+ UnCondBrIter = I;
+
if (!AllowModify) {
TBB = I->getOperand(0).getMBB();
continue;
@@ -1718,10 +1721,11 @@
TBB = 0;
I->eraseFromParent();
I = MBB.end();
+ UnCondBrIter = MBB.end();
continue;
}
- // TBB is used to indicate the unconditinal destination.
+ // TBB is used to indicate the unconditional destination.
TBB = I->getOperand(0).getMBB();
continue;
}
@@ -1733,6 +1737,45 @@
// Working from the bottom, handle the first conditional branch.
if (Cond.empty()) {
+ MachineBasicBlock *TargetBB = I->getOperand(0).getMBB();
+ if (AllowModify && UnCondBrIter != MBB.end() &&
+ MBB.isLayoutSuccessor(TargetBB)) {
+ // If we can modify the code and it ends in something like:
+ //
+ // jCC L1
+ // jmp L2
+ // L1:
+ // ...
+ // L2:
+ //
+ // Then we can change this to:
+ //
+ // jnCC L2
+ // L1:
+ // ...
+ // L2:
+ //
+ // Which is a bit more efficient.
+ // We conditionally jump to the fall-through block.
+ BranchCode = GetOppositeBranchCondition(BranchCode);
+ unsigned JNCC = GetCondBranchFromCond(BranchCode);
+ MachineBasicBlock::iterator OldInst = I;
+
+ BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(JNCC))
+ .addMBB(UnCondBrIter->getOperand(0).getMBB());
+ BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(X86::JMP_4))
+ .addMBB(TargetBB);
+ MBB.addSuccessor(TargetBB);
+
+ OldInst->eraseFromParent();
+ UnCondBrIter->eraseFromParent();
+
+ // Restart the analysis.
+ UnCondBrIter = MBB.end();
+ I = MBB.end();
+ continue;
+ }
+
FBB = TBB;
TBB = I->getOperand(0).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
Added: llvm/trunk/test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll?rev=101162&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2010-04-13-AnalyzeBranchCrash.ll Tue Apr 13 13:50:27 2010
@@ -0,0 +1,42 @@
+; RUN: llc < %s -mtriple=i386-apple-darwin -mcpu=core2
+; rdar://7857830
+
+%0 = type opaque
+%1 = type opaque
+
+define void @t(%0* %self, i8* nocapture %_cmd, %1* %scroller, i32 %hitPart, float %multiplier) nounwind optsize ssp {
+entry:
+ switch i32 %hitPart, label %if.else [
+ i32 7, label %if.then
+ i32 8, label %if.then
+ ]
+
+if.then: ; preds = %entry, %entry
+ %tmp69 = load float* null, align 4 ; <float> [#uses=1]
+ %cmp19 = icmp eq %1* null, %scroller ; <i1> [#uses=2]
+ %cond = select i1 %cmp19, float %tmp69, float 0.000000e+00 ; <float> [#uses=1]
+ %call36 = call i64 bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to i64 (i8*, i8*)*)(i8* undef, i8* undef) nounwind optsize ; <i64> [#uses=2]
+ br i1 %cmp19, label %cond.true32, label %cond.false39
+
+cond.true32: ; preds = %if.then
+ %sroa.store.elt68 = lshr i64 %call36, 32 ; <i64> [#uses=1]
+ %0 = trunc i64 %sroa.store.elt68 to i32 ; <i32> [#uses=1]
+ br label %cond.end47
+
+cond.false39: ; preds = %if.then
+ %1 = trunc i64 %call36 to i32 ; <i32> [#uses=1]
+ br label %cond.end47
+
+cond.end47: ; preds = %cond.false39, %cond.true32
+ %cond48.in = phi i32 [ %0, %cond.true32 ], [ %1, %cond.false39 ] ; <i32> [#uses=1]
+ %cond48 = bitcast i32 %cond48.in to float ; <float> [#uses=1]
+ %div = fdiv float %cond, undef ; <float> [#uses=1]
+ %div58 = fdiv float %div, %cond48 ; <float> [#uses=1]
+ call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*, float)*)(i8* undef, i8* undef, float %div58) nounwind optsize
+ ret void
+
+if.else: ; preds = %entry
+ ret void
+}
+
+declare i8* @objc_msgSend(i8*, i8*, ...)
Modified: llvm/trunk/test/CodeGen/X86/brcond.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/brcond.ll?rev=101162&r1=101161&r2=101162&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/brcond.ll (original)
+++ llvm/trunk/test/CodeGen/X86/brcond.ll Tue Apr 13 13:50:27 2010
@@ -67,3 +67,42 @@
; CHECK-NEXT: orl 8(%esp), %eax
; CHECK-NEXT: je LBB3_2
}
+
+; <rdar://problem/7598384>:
+;
+; jCC L1
+; jmp L2
+; L1:
+; ...
+; L2:
+; ...
+;
+; to:
+;
+; jnCC L2
+; L1:
+; ...
+; L2:
+; ...
+define float @test4(float %x, float %y) nounwind readnone optsize ssp {
+entry:
+ %0 = fpext float %x to double ; <double> [#uses=1]
+ %1 = fpext float %y to double ; <double> [#uses=1]
+ %2 = fmul double %0, %1 ; <double> [#uses=3]
+ %3 = fcmp oeq double %2, 0.000000e+00 ; <i1> [#uses=1]
+ br i1 %3, label %bb2, label %bb1
+
+; CHECK: jne
+; CHECK-NEXT: jnp
+; CHECK-NOT: jmp
+; CHECK: LBB
+
+bb1: ; preds = %entry
+ %4 = fadd double %2, -1.000000e+00 ; <double> [#uses=1]
+ br label %bb2
+
+bb2: ; preds = %entry, %bb1
+ %.0.in = phi double [ %4, %bb1 ], [ %2, %entry ] ; <double> [#uses=1]
+ %.0 = fptrunc double %.0.in to float ; <float> [#uses=1]
+ ret float %.0
+}
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