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llvm-6502/test/Transforms/IndVarSimplify/promote-iv-to-eliminate-casts.ll

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Use a sign-extend instead of a zero-extend when promoting a trip count value when the original loop iteration condition is signed and the canonical induction variable won't undergo signed overflow. This isn't required for correctness; it just preserves more information about original loop iteration values. Add a getTruncateOrSignExtend method to ScalarEvolution, following getTruncateOrZeroExtend. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64918 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-18 17:22:41 +00:00
; RUN: llvm-as < %s | opt -indvars | llvm-dis > %t
Back out the change in 64918 that used sign-extensions when promoting trip counts that use signed comparisons. It's not obviously the best approach for preserving trip count information, and at any rate there isn't anything in the tree right now that makes use of that, so for now always using zero-extensions is preferable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65347 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-23 23:20:35 +00:00
; RUN: not grep sext %t
Teach IndVarSimplify to optimize code using the C "int" type for loop induction on LP64 targets. When the induction variable is used in addressing, IndVars now is usually able to inserst a 64-bit induction variable and eliminates the sign-extending cast. This is also useful for code using C "short" types for induction variables on targets with 32-bit addressing. Inserting a wider induction variable is easy; the tricky part is determining when trunc(sext(i)) expressions are no-ops. This requires range analysis of the loop trip count. A common case is when the original loop iteration starts at 0 and exits when the induction variable is signed-less-than a fixed value; this case is now handled. This replaces IndVarSimplify's OptimizeCanonicalIVType. It was doing the same optimization, but it was limited to loops with constant trip counts, because it was running after the loop rewrite, and the information about the original induction variable is lost by that point. Rename ScalarEvolution's executesAtLeastOnce to isLoopGuardedByCond, generalize it to be able to test for ICMP_NE conditions, and move it to be a public function so that IndVars can use it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64407 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-12 22:19:27 +00:00
define i64 @test(i64* nocapture %first, i32 %count) nounwind readonly {
entry:
%t0 = icmp sgt i32 %count, 0 ; <i1> [#uses=1]
br i1 %t0, label %bb.nph, label %bb2
bb.nph: ; preds = %entry
br label %bb
bb: ; preds = %bb1, %bb.nph
%result.02 = phi i64 [ %t5, %bb1 ], [ 0, %bb.nph ] ; <i64> [#uses=1]
%n.01 = phi i32 [ %t6, %bb1 ], [ 0, %bb.nph ] ; <i32> [#uses=2]
%t1 = sext i32 %n.01 to i64 ; <i64> [#uses=1]
%t2 = getelementptr i64* %first, i64 %t1 ; <i64*> [#uses=1]
%t3 = load i64* %t2, align 8 ; <i64> [#uses=1]
%t4 = lshr i64 %t3, 4 ; <i64> [#uses=1]
%t5 = add i64 %t4, %result.02 ; <i64> [#uses=2]
%t6 = add i32 %n.01, 1 ; <i32> [#uses=2]
br label %bb1
bb1: ; preds = %bb
%t7 = icmp slt i32 %t6, %count ; <i1> [#uses=1]
br i1 %t7, label %bb, label %bb1.bb2_crit_edge
bb1.bb2_crit_edge: ; preds = %bb1
%.lcssa = phi i64 [ %t5, %bb1 ] ; <i64> [#uses=1]
br label %bb2
bb2: ; preds = %bb1.bb2_crit_edge, %entry
%result.0.lcssa = phi i64 [ %.lcssa, %bb1.bb2_crit_edge ], [ 0, %entry ] ; <i64> [#uses=1]
ret i64 %result.0.lcssa
}
define void @foo(i16 signext %N, i32* nocapture %P) nounwind {
entry:
%t0 = icmp sgt i16 %N, 0 ; <i1> [#uses=1]
br i1 %t0, label %bb.nph, label %return
bb.nph: ; preds = %entry
br label %bb
bb: ; preds = %bb1, %bb.nph
%i.01 = phi i16 [ %t3, %bb1 ], [ 0, %bb.nph ] ; <i16> [#uses=2]
%t1 = sext i16 %i.01 to i64 ; <i64> [#uses=1]
%t2 = getelementptr i32* %P, i64 %t1 ; <i32*> [#uses=1]
store i32 123, i32* %t2, align 4
%t3 = add i16 %i.01, 1 ; <i16> [#uses=2]
br label %bb1
bb1: ; preds = %bb
%t4 = icmp slt i16 %t3, %N ; <i1> [#uses=1]
br i1 %t4, label %bb, label %bb1.return_crit_edge
bb1.return_crit_edge: ; preds = %bb1
br label %return
return: ; preds = %bb1.return_crit_edge, %entry
ret void
}
Extend the IndVarSimplify support for promoting induction variables: - Test for signed and unsigned wrapping conditions, instead of just testing for non-negative induction ranges. - Handle loops with GT comparisons, in addition to LT comparisons. - Support more cases of induction variables that don't start at 0. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64532 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-14 02:31:09 +00:00
; Test cases from PR1301:
define void @kinds__srangezero([21 x i32]* nocapture %a) nounwind {
bb.thread:
br label %bb
bb: ; preds = %bb, %bb.thread
%i.0.reg2mem.0 = phi i8 [ -10, %bb.thread ], [ %tmp7, %bb ] ; <i8> [#uses=2]
%tmp12 = sext i8 %i.0.reg2mem.0 to i32 ; <i32> [#uses=1]
%tmp4 = add i32 %tmp12, 10 ; <i32> [#uses=1]
%tmp5 = getelementptr [21 x i32]* %a, i32 0, i32 %tmp4 ; <i32*> [#uses=1]
store i32 0, i32* %tmp5
%tmp7 = add i8 %i.0.reg2mem.0, 1 ; <i8> [#uses=2]
%0 = icmp sgt i8 %tmp7, 10 ; <i1> [#uses=1]
br i1 %0, label %return, label %bb
return: ; preds = %bb
ret void
}
define void @kinds__urangezero([21 x i32]* nocapture %a) nounwind {
bb.thread:
br label %bb
bb: ; preds = %bb, %bb.thread
%i.0.reg2mem.0 = phi i8 [ 10, %bb.thread ], [ %tmp7, %bb ] ; <i8> [#uses=2]
%tmp12 = sext i8 %i.0.reg2mem.0 to i32 ; <i32> [#uses=1]
%tmp4 = add i32 %tmp12, -10 ; <i32> [#uses=1]
%tmp5 = getelementptr [21 x i32]* %a, i32 0, i32 %tmp4 ; <i32*> [#uses=1]
store i32 0, i32* %tmp5
%tmp7 = add i8 %i.0.reg2mem.0, 1 ; <i8> [#uses=2]
%0 = icmp sgt i8 %tmp7, 30 ; <i1> [#uses=1]
br i1 %0, label %return, label %bb
return: ; preds = %bb
ret void
}
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