[llvm-commits] [llvm] r127064 - in /llvm/trunk: lib/Analysis/InstructionSimplify.cpp lib/Transforms/InstCombine/InstCombineCompares.cpp test/Transforms/InstCombine/icmp.ll test/Transforms/InstSimplify/compare.ll
Nick Lewycky
nicholas at mxc.ca
Fri Mar 4 21:19:11 PST 2011
Author: nicholas
Date: Fri Mar 4 23:19:11 2011
New Revision: 127064
URL: http://llvm.org/viewvc/llvm-project?rev=127064&view=rev
Log:
Thread comparisons over udiv/sdiv/ashr/lshr exact and lshr nuw/nsw whenever
possible. This goes into instcombine and instsimplify because instsimplify
doesn't need to check hasOneUse since it returns (almost exclusively) constants.
This fixes PR9343 #4 #5 and #8!
Modified:
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/icmp.ll
llvm/trunk/test/Transforms/InstSimplify/compare.ll
Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=127064&r1=127063&r2=127064&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Mar 4 23:19:11 2011
@@ -1344,7 +1344,7 @@
// the compare, and if only one of them is then we moved it to RHS already.
if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
isa<ConstantPointerNull>(RHS)))
- // We already know that LHS != LHS.
+ // We already know that LHS != RHS.
return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
// If we are comparing with zero then try hard since this is a common case.
@@ -1700,6 +1700,38 @@
}
}
+ if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
+ LBO->getOperand(1) == RBO->getOperand(1)) {
+ switch (LBO->getOpcode()) {
+ default: break;
+ case Instruction::UDiv:
+ case Instruction::LShr:
+ if (ICmpInst::isSigned(Pred))
+ break;
+ // fall-through
+ case Instruction::SDiv:
+ case Instruction::AShr:
+ if (!LBO->isExact() && !RBO->isExact())
+ break;
+ if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+ RBO->getOperand(0), TD, DT, MaxRecurse-1))
+ return V;
+ break;
+ case Instruction::Shl: {
+ bool NUW = LBO->hasNoUnsignedWrap() && LBO->hasNoUnsignedWrap();
+ bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
+ if (!NUW && !NSW)
+ break;
+ if (!NSW && ICmpInst::isSigned(Pred))
+ break;
+ if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+ RBO->getOperand(0), TD, DT, MaxRecurse-1))
+ return V;
+ break;
+ }
+ }
+ }
+
// If the comparison is with the result of a select instruction, check whether
// comparing with either branch of the select always yields the same value.
if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS))
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=127064&r1=127063&r2=127064&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Fri Mar 4 23:19:11 2011
@@ -2393,6 +2393,27 @@
}
}
break;
+ case Instruction::UDiv:
+ case Instruction::LShr:
+ if (I.isSigned())
+ break;
+ // fall-through
+ case Instruction::SDiv:
+ case Instruction::AShr:
+ if (!BO0->isExact() && !BO1->isExact())
+ break;
+ return new ICmpInst(I.getPredicate(), BO0->getOperand(0),
+ BO1->getOperand(0));
+ case Instruction::Shl: {
+ bool NUW = BO0->hasNoUnsignedWrap() && BO1->hasNoUnsignedWrap();
+ bool NSW = BO0->hasNoSignedWrap() && BO1->hasNoSignedWrap();
+ if (!NUW && !NSW)
+ break;
+ if (!NSW && I.isSigned())
+ break;
+ return new ICmpInst(I.getPredicate(), BO0->getOperand(0),
+ BO1->getOperand(0));
+ }
}
}
}
Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=127064&r1=127063&r2=127064&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Fri Mar 4 23:19:11 2011
@@ -419,3 +419,49 @@
%B = icmp slt i32 %Y, %A
ret i1 %B
}
+
+; CHECK: @test44
+; CHECK: %B = icmp sgt i32 %Y, -1
+define i1 @test44(i32 %X, i32 %Y) {
+ %A = srem i32 %X, %Y
+ %B = icmp slt i32 %A, %Y
+ ret i1 %B
+}
+
+; CHECK: @test45
+; CHECK: %B = icmp slt i32 %Y, 0
+define i1 @test45(i32 %X, i32 %Y) {
+ %A = srem i32 %X, %Y
+ %B = icmp slt i32 %Y, %A
+ ret i1 %B
+}
+
+; PR9343 #4
+; CHECK: @test46
+; CHECK: %C = icmp ult i32 %X, %Y
+define i1 @test46(i32 %X, i32 %Y, i32 %Z) {
+ %A = ashr exact i32 %X, %Z
+ %B = ashr exact i32 %Y, %Z
+ %C = icmp ult i32 %A, %B
+ ret i1 %C
+}
+
+; PR9343 #5
+; CHECK: @test47
+; CHECK: %C = icmp ugt i32 %X, %Y
+define i1 @test47(i32 %X, i32 %Y, i32 %Z) {
+ %A = ashr exact i32 %X, %Z
+ %B = ashr exact i32 %Y, %Z
+ %C = icmp ugt i32 %A, %B
+ ret i1 %C
+}
+
+; PR9343 #8
+; CHECK: @test48
+; CHECK: %C = icmp eq i32 %X, %Y
+define i1 @test48(i32 %X, i32 %Y, i32 %Z) {
+ %A = sdiv exact i32 %X, %Z
+ %B = sdiv exact i32 %Y, %Z
+ %C = icmp eq i32 %A, %B
+ ret i1 %C
+}
Modified: llvm/trunk/test/Transforms/InstSimplify/compare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/compare.ll?rev=127064&r1=127063&r2=127064&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/compare.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/compare.ll Fri Mar 4 23:19:11 2011
@@ -261,6 +261,15 @@
; CHECK: ret i1 true
}
+define i1 @udiv2(i32 %X, i32 %Y, i32 %Z) {
+; CHECK: @udiv2
+ %A = udiv exact i32 10, %Z
+ %B = udiv exact i32 20, %Z
+ %C = icmp ult i32 %A, %B
+ ret i1 %C
+; CHECK: ret i1 true
+}
+
define i1 @sdiv1(i32 %X) {
; CHECK: @sdiv1
%A = sdiv i32 %X, 1000000
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