[llvm] r265411 - [lanai] LanaiSetflagAluCombiner more conservative
Jacques Pienaar via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 5 09:18:14 PDT 2016
Author: jpienaar
Date: Tue Apr 5 11:18:13 2016
New Revision: 265411
URL: http://llvm.org/viewvc/llvm-project?rev=265411&view=rev
Log:
[lanai] LanaiSetflagAluCombiner more conservative
Summary: LanaiSetflagAluCombiner could previously combine instructions across basic building blocks even when not legal. Make the LanaiSetflagAluCombiner more conservative to avoid this.
Reviewers: eliben
Subscribers: joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D18746
Modified:
llvm/trunk/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp
llvm/trunk/test/CodeGen/Lanai/combined_alu_setcc.ll
Modified: llvm/trunk/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp?rev=265411&r1=265410&r2=265411&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp (original)
+++ llvm/trunk/lib/Target/Lanai/LanaiSetflagAluCombiner.cpp Tue Apr 5 11:18:13 2016
@@ -233,20 +233,22 @@ static bool isSuitableSetflag(MbbIterato
MbbIterator SCCUserIter = Instruction;
while (SCCUserIter != End) {
++SCCUserIter;
- // Early exit when encountering flag setting instruction.
- if (isFlagSettingInstruction(SCCUserIter->getOpcode()))
- break;
+ // Early exit when encountering flag setting or return instruction.
+ if (isFlagSettingInstruction(SCCUserIter->getOpcode()) ||
+ SCCUserIter->isReturn())
+ // Only return true if flags are set post the flag setting instruction
+ // tested or a return is executed.
+ return true;
int CCIndex = getCCOperandPosition(SCCUserIter->getOpcode());
if (CCIndex != -1) {
LPCC::CondCode CC = static_cast<LPCC::CondCode>(
SCCUserIter->getOperand(CCIndex).getImm());
+ // Return false if the flag is used outside of a EQ, NE, PL and MI.
if (CC != LPCC::ICC_EQ && CC != LPCC::ICC_NE && CC != LPCC::ICC_PL &&
CC != LPCC::ICC_MI)
return false;
}
}
-
- return true;
}
return false;
Modified: llvm/trunk/test/CodeGen/Lanai/combined_alu_setcc.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Lanai/combined_alu_setcc.ll?rev=265411&r1=265410&r2=265411&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Lanai/combined_alu_setcc.ll (original)
+++ llvm/trunk/test/CodeGen/Lanai/combined_alu_setcc.ll Tue Apr 5 11:18:13 2016
@@ -121,6 +121,50 @@ return:
ret i32 %retval.0
}
; CHECK-LABEL: test4
-; CHECK: and.f
-; CHECK: and.f
-; CHECK: and.f
+; TODO: Re-enable test. This test is disabled post making the combiner more
+; conservative.
+; DISABLED_CHECK: and.f
+
+; Test to avoid incorrect fusing that spans across basic blocks
+ at a = global i32 -1, align 4
+ at b = global i32 0, align 4
+
+; Function Attrs: nounwind
+define void @testBB() {
+entry:
+ %0 = load i32, i32* @a, align 4, !tbaa !1
+ %1 = load i32, i32* @b, align 4, !tbaa !1
+ %sub.i = sub i32 %1, %0
+ %tobool = icmp sgt i32 %sub.i, -1
+ br i1 %tobool, label %if.end, label %if.then
+
+if.then: ; preds = %entry
+ %call1 = tail call i32 bitcast (i32 (...)* @g to i32 ()*)()
+ br label %while.body
+
+while.body: ; preds = %if.then, %while.body
+ br label %while.body
+
+if.end: ; preds = %entry
+ %cmp.i = icmp slt i32 %sub.i, 1
+ br i1 %cmp.i, label %if.then4, label %if.end7
+
+if.then4: ; preds = %if.end
+ %call5 = tail call i32 bitcast (i32 (...)* @g to i32 ()*)()
+ br label %while.body6
+
+while.body6: ; preds = %if.then4, %while.body6
+ br label %while.body6
+
+if.end7: ; preds = %if.end
+ ret void
+}
+
+declare i32 @g(...)
+; CHECK-LABEL: testBB
+; CHECK: sub.f {{.*}}, %r0
+
+!1 = !{!2, !2, i64 0}
+!2 = !{!"int", !3, i64 0}
+!3 = !{!"omnipotent char", !4, i64 0}
+!4 = !{!"Simple C/C++ TBAA"}
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