[llvm-commits] [llvm] r102234 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll test/Analysis/ScalarEvolution/sle.ll
Dan Gohman
gohman at apple.com
Fri Apr 23 20:09:42 PDT 2010
Author: djg
Date: Fri Apr 23 22:09:42 2010
New Revision: 102234
URL: http://llvm.org/viewvc/llvm-project?rev=102234&view=rev
Log:
ScalarEvolution support for <= and >= loops.
Also, generalize ScalarEvolutions's min and max recognition to handle
some new forms of min and max that this change makes more common.
Added:
llvm/trunk/test/Analysis/ScalarEvolution/sle.ll
Modified:
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
llvm/trunk/test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll
llvm/trunk/test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll
llvm/trunk/test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=102234&r1=102233&r2=102234&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Fri Apr 23 22:09:42 2010
@@ -3416,10 +3416,22 @@
// fall through
case ICmpInst::ICMP_SGT:
case ICmpInst::ICMP_SGE:
- if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
- return getSMaxExpr(getSCEV(LHS), getSCEV(RHS));
- else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- return getSMinExpr(getSCEV(LHS), getSCEV(RHS));
+ // a >s b ? a+x : b+x -> smax(a, b)+x
+ // a >s b ? b+x : a+x -> smin(a, b)+x
+ if (LHS->getType() == U->getType()) {
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *RS = getSCEV(RHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, RS);
+ if (LDiff == RDiff)
+ return getAddExpr(getSMaxExpr(LS, RS), LDiff);
+ LDiff = getMinusSCEV(LA, RS);
+ RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getSMinExpr(LS, RS), LDiff);
+ }
break;
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_ULE:
@@ -3427,28 +3439,52 @@
// fall through
case ICmpInst::ICMP_UGT:
case ICmpInst::ICMP_UGE:
- if (LHS == U->getOperand(1) && RHS == U->getOperand(2))
- return getUMaxExpr(getSCEV(LHS), getSCEV(RHS));
- else if (LHS == U->getOperand(2) && RHS == U->getOperand(1))
- return getUMinExpr(getSCEV(LHS), getSCEV(RHS));
+ // a >u b ? a+x : b+x -> umax(a, b)+x
+ // a >u b ? b+x : a+x -> umin(a, b)+x
+ if (LHS->getType() == U->getType()) {
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *RS = getSCEV(RHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, RS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, RS), LDiff);
+ LDiff = getMinusSCEV(LA, RS);
+ RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMinExpr(LS, RS), LDiff);
+ }
break;
case ICmpInst::ICMP_NE:
- // n != 0 ? n : 1 -> umax(n, 1)
- if (LHS == U->getOperand(1) &&
- isa<ConstantInt>(U->getOperand(2)) &&
- cast<ConstantInt>(U->getOperand(2))->isOne() &&
+ // n != 0 ? n+x : 1+x -> umax(n, 1)+x
+ if (LHS->getType() == U->getType() &&
isa<ConstantInt>(RHS) &&
- cast<ConstantInt>(RHS)->isZero())
- return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(2)));
+ cast<ConstantInt>(RHS)->isZero()) {
+ const SCEV *One = getConstant(LHS->getType(), 1);
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, LS);
+ const SCEV *RDiff = getMinusSCEV(RA, One);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ }
break;
case ICmpInst::ICMP_EQ:
- // n == 0 ? 1 : n -> umax(n, 1)
- if (LHS == U->getOperand(2) &&
- isa<ConstantInt>(U->getOperand(1)) &&
- cast<ConstantInt>(U->getOperand(1))->isOne() &&
+ // n == 0 ? 1+x : n+x -> umax(n, 1)+x
+ if (LHS->getType() == U->getType() &&
isa<ConstantInt>(RHS) &&
- cast<ConstantInt>(RHS)->isZero())
- return getUMaxExpr(getSCEV(LHS), getSCEV(U->getOperand(1)));
+ cast<ConstantInt>(RHS)->isZero()) {
+ const SCEV *One = getConstant(LHS->getType(), 1);
+ const SCEV *LS = getSCEV(LHS);
+ const SCEV *LA = getSCEV(U->getOperand(1));
+ const SCEV *RA = getSCEV(U->getOperand(2));
+ const SCEV *LDiff = getMinusSCEV(LA, One);
+ const SCEV *RDiff = getMinusSCEV(RA, LS);
+ if (LDiff == RDiff)
+ return getAddExpr(getUMaxExpr(LS, One), LDiff);
+ }
break;
default:
break;
@@ -3885,6 +3921,57 @@
if (!isa<SCEVCouldNotCompute>(Ret)) return Ret;
}
+ // If possible, canonicalize GE/LE comparisons to GT/LT comparisons, by
+ // adding or subtracting 1 from one of the operands.
+ switch (Cond) {
+ case ICmpInst::ICMP_SLE:
+ if (!getSignedRange(RHS).getSignedMax().isMaxSignedValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), 1, true), RHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Cond = ICmpInst::ICMP_SLT;
+ } else if (!getSignedRange(LHS).getSignedMin().isMinSignedValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), -1, true), LHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Cond = ICmpInst::ICMP_SLT;
+ }
+ break;
+ case ICmpInst::ICMP_SGE:
+ if (!getSignedRange(RHS).getSignedMin().isMinSignedValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), -1, true), RHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Cond = ICmpInst::ICMP_SGT;
+ } else if (!getSignedRange(LHS).getSignedMax().isMaxSignedValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), 1, true), LHS,
+ /*HasNUW=*/false, /*HasNSW=*/true);
+ Cond = ICmpInst::ICMP_SGT;
+ }
+ break;
+ case ICmpInst::ICMP_ULE:
+ if (!getUnsignedRange(RHS).getUnsignedMax().isMaxValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), 1, false), RHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Cond = ICmpInst::ICMP_ULT;
+ } else if (!getUnsignedRange(LHS).getUnsignedMin().isMinValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), -1, false), LHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Cond = ICmpInst::ICMP_ULT;
+ }
+ break;
+ case ICmpInst::ICMP_UGE:
+ if (!getUnsignedRange(RHS).getUnsignedMin().isMinValue()) {
+ RHS = getAddExpr(getConstant(RHS->getType(), -1, false), RHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Cond = ICmpInst::ICMP_UGT;
+ } else if (!getUnsignedRange(LHS).getUnsignedMax().isMaxValue()) {
+ LHS = getAddExpr(getConstant(RHS->getType(), 1, false), LHS,
+ /*HasNUW=*/true, /*HasNSW=*/false);
+ Cond = ICmpInst::ICMP_UGT;
+ }
+ break;
+ default:
+ break;
+ }
+
switch (Cond) {
case ICmpInst::ICMP_NE: { // while (X != Y)
// Convert to: while (X-Y != 0)
Modified: llvm/trunk/test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll?rev=102234&r1=102233&r2=102234&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2008-11-18-LessThanOrEqual.ll Fri Apr 23 22:09:42 2010
@@ -1,6 +1,5 @@
; RUN: opt < %s -analyze -scalar-evolution |& \
; RUN: grep {Loop %bb: backedge-taken count is (7 + (-1 \\* %argc))}
-; XFAIL: *
define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
Modified: llvm/trunk/test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll?rev=102234&r1=102233&r2=102234&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2008-12-08-FiniteSGE.ll Fri Apr 23 22:09:42 2010
@@ -1,5 +1,4 @@
; RUN: opt < %s -analyze -scalar-evolution | grep {backedge-taken count is 255}
-; XFAIL: *
define i32 @foo(i32 %x, i32 %y, i32* %lam, i32* %alp) nounwind {
bb1.thread:
Modified: llvm/trunk/test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll?rev=102234&r1=102233&r2=102234&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2008-12-11-SMaxOverflow.ll Fri Apr 23 22:09:42 2010
@@ -1,5 +1,7 @@
-; RUN: opt < %s -analyze -scalar-evolution | grep {0 smax}
-; XFAIL: *
+; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
+
+; CHECK: @f
+; CHECK: Loop %bb16.preheader: backedge-taken count is (-1 + %c.idx.val)
define i32 @f(i32 %c.idx.val) {
Added: llvm/trunk/test/Analysis/ScalarEvolution/sle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/sle.ll?rev=102234&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/sle.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/sle.ll Fri Apr 23 22:09:42 2010
@@ -0,0 +1,27 @@
+; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
+
+; ScalarEvolution should be able to use nsw information to prove that
+; this loop has a finite trip count.
+
+; CHECK: @le
+; CHECK: Loop %for.body: backedge-taken count is %n
+; CHECK: Loop %for.body: max backedge-taken count is 9223372036854775807
+
+define void @le(i64 %n, double* nocapture %p) nounwind {
+entry:
+ %cmp6 = icmp slt i64 %n, 0 ; <i1> [#uses=1]
+ br i1 %cmp6, label %for.end, label %for.body
+
+for.body: ; preds = %for.body, %entry
+ %i = phi i64 [ %i.next, %for.body ], [ 0, %entry ] ; <i64> [#uses=2]
+ %arrayidx = getelementptr double* %p, i64 %i ; <double*> [#uses=2]
+ %t4 = load double* %arrayidx ; <double> [#uses=1]
+ %mul = fmul double %t4, 2.200000e+00 ; <double> [#uses=1]
+ store double %mul, double* %arrayidx
+ %i.next = add nsw i64 %i, 1 ; <i64> [#uses=2]
+ %cmp = icmp sgt i64 %i.next, %n ; <i1> [#uses=1]
+ br i1 %cmp, label %for.end, label %for.body
+
+for.end: ; preds = %for.body, %entry
+ ret void
+}
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