[llvm] r307244 - Revert "Revert "[IndVars] Canonicalize comparisons between non-negative values and indvars""
Max Kazantsev via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 6 02:57:41 PDT 2017
Author: mkazantsev
Date: Thu Jul 6 02:57:41 2017
New Revision: 307244
URL: http://llvm.org/viewvc/llvm-project?rev=307244&view=rev
Log:
Revert "Revert "[IndVars] Canonicalize comparisons between non-negative values and indvars""
It seems that the patch was reverted by mistake. Clang testing showed failure of the
MathExtras.SaturatingMultiply test, however I was unable to reproduce the issue on the
fresh code base and was able to confirm that the transformation introduced by the change
does not happen in the said test. This gives a strong confidence that the actual reason of
the failure of the initial patch was somewhere else, and that problem now seems to be
fixed. Re-submitting the change to confirm that.
Added:
llvm/trunk/test/Transforms/IndVarSimplify/canonicalize-cmp.ll
Modified:
llvm/trunk/lib/Transforms/Utils/SimplifyIndVar.cpp
llvm/trunk/test/Analysis/ScalarEvolution/guards.ll
llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll
llvm/trunk/test/Transforms/IndVarSimplify/widen-loop-comp.ll
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyIndVar.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyIndVar.cpp?rev=307244&r1=307243&r2=307244&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyIndVar.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyIndVar.cpp Thu Jul 6 02:57:41 2017
@@ -264,6 +264,10 @@ void SimplifyIndvar::eliminateIVComparis
ICmp->setPredicate(InvariantPredicate);
ICmp->setOperand(0, NewLHS);
ICmp->setOperand(1, NewRHS);
+ } else if (ICmpInst::isSigned(Pred) &&
+ SE->isKnownNonNegative(S) && SE->isKnownNonNegative(X)) {
+ DEBUG(dbgs() << "INDVARS: Turn to unsigned comparison: " << *ICmp << '\n');
+ ICmp->setPredicate(ICmpInst::getUnsignedPredicate(Pred));
} else
return;
Modified: llvm/trunk/test/Analysis/ScalarEvolution/guards.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/guards.ll?rev=307244&r1=307243&r2=307244&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/guards.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/guards.ll Thu Jul 6 02:57:41 2017
@@ -19,7 +19,7 @@ entry:
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
-; CHECK: %iv.inc.cmp = icmp slt i32 %iv.inc, %len
+; CHECK: %iv.inc.cmp = icmp ult i32 %iv.inc, %len
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
; CHECK: leave:
@@ -41,7 +41,7 @@ leave:
define void @test_2(i32 %n, i32* %len_buf) {
; CHECK-LABEL: @test_2(
-; CHECK: [[LEN_SEXT:%[^ ]+]] = sext i32 %len to i64
+; CHECK: [[LEN_ZEXT:%[^ ]+]] = zext i32 %len to i64
; CHECK: br label %loop
entry:
@@ -52,7 +52,7 @@ loop:
; CHECK: loop:
; CHECK: %indvars.iv = phi i64 [ %indvars.iv.next, %loop ], [ 0, %entry ]
; CHECK: %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-; CHECK: %iv.inc.cmp = icmp slt i64 %indvars.iv.next, [[LEN_SEXT]]
+; CHECK: %iv.inc.cmp = icmp ult i64 %indvars.iv.next, [[LEN_ZEXT]]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %iv.inc.cmp) [ "deopt"() ]
; CHECK: leave:
Added: llvm/trunk/test/Transforms/IndVarSimplify/canonicalize-cmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/canonicalize-cmp.ll?rev=307244&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/canonicalize-cmp.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/canonicalize-cmp.ll Thu Jul 6 02:57:41 2017
@@ -0,0 +1,52 @@
+; RUN: opt -S -indvars < %s | FileCheck %s
+
+; Check that we replace signed comparisons between non-negative values with
+; unsigned comparisons if we can.
+
+target datalayout = "n8:16:32:64"
+
+define i32 @test_01(i32 %a, i32 %b, i32* %p) {
+
+; CHECK-LABEL: @test_01(
+; CHECK-NOT: icmp slt
+; CHECK: %cmp1 = icmp ult i32 %iv, 100
+; CHECK: %cmp2 = icmp ult i32 %iv, 100
+; CHECK-NOT: %cmp3
+; CHECK: %exitcond = icmp ne i32 %iv.next, 1000
+
+entry:
+ br label %loop.entry
+
+loop.entry:
+ %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.be ]
+ %cmp1 = icmp slt i32 %iv, 100
+ br i1 %cmp1, label %b1, label %b2
+
+b1:
+ store i32 %iv, i32* %p
+ br label %merge
+
+b2:
+ store i32 %a, i32* %p
+ br label %merge
+
+merge:
+ %cmp2 = icmp ult i32 %iv, 100
+ br i1 %cmp2, label %b3, label %b4
+
+b3:
+ store i32 %iv, i32* %p
+ br label %loop.be
+
+b4:
+ store i32 %b, i32* %p
+ br label %loop.be
+
+loop.be:
+ %iv.next = add i32 %iv, 1
+ %cmp3 = icmp slt i32 %iv.next, 1000
+ br i1 %cmp3, label %loop.entry, label %exit
+
+exit:
+ ret i32 %iv
+}
Modified: llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll?rev=307244&r1=307243&r2=307244&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll (original)
+++ llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll Thu Jul 6 02:57:41 2017
@@ -111,7 +111,7 @@ return:
; Indvars should not turn the second loop into an infinite one.
; CHECK-LABEL: @func_11(
-; CHECK: %tmp5 = icmp slt i32 %__key6.0, 10
+; CHECK: %tmp5 = icmp ult i32 %__key6.0, 10
; CHECK-NOT: br i1 true, label %noassert68, label %unrolledend
define i32 @func_11() nounwind uwtable {
@@ -163,7 +163,7 @@ declare void @llvm.trap() noreturn nounw
; In this case the second loop only has a single iteration, fold the header away
; CHECK-LABEL: @func_12(
-; CHECK: %tmp5 = icmp slt i32 %__key6.0, 10
+; CHECK: %tmp5 = icmp ult i32 %__key6.0, 10
; CHECK: br i1 true, label %noassert68, label %unrolledend
define i32 @func_12() nounwind uwtable {
entry:
Modified: llvm/trunk/test/Transforms/IndVarSimplify/widen-loop-comp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/widen-loop-comp.ll?rev=307244&r1=307243&r2=307244&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/widen-loop-comp.ll (original)
+++ llvm/trunk/test/Transforms/IndVarSimplify/widen-loop-comp.ll Thu Jul 6 02:57:41 2017
@@ -64,7 +64,7 @@ for.end:
; CHECK-LABEL: @test2
; CHECK: for.body4.us
; CHECK: %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
-; CHECK: %cmp2.us = icmp slt i64
+; CHECK: %cmp2.us = icmp ult i64
; CHECK-NOT: %2 = trunc i64 %indvars.iv.next to i32
; CHECK-NOT: %cmp2.us = icmp slt i32
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