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llvm-mirror/test/Analysis/ScalarEvolution/fold.ll
Nick Lewycky baf1d18cf0 Teach SCEV to handle more cases of 'and X, CST', specifically where CST is any number of contiguous 1 bits in a row, with any number of leading and trailing 0 bits.
Unfortunately, this in turn led to some lower quality SCEVs due to some different paths through expression simplification, so add getUDivExactExpr and use it. This fixes all instances of the problems that I found, but we can make that function smarter as necessary.

Merge test "xor-and.ll" into "and-xor.ll" since I needed to update it anyways. Test 'nsw-offset.ll' analyzes a little deeper, %n now gets a scev in terms of %no instead of a SCEVUnknown.

llvm-svn: 200203
2014-01-27 10:04:03 +00:00

80 lines
1.9 KiB
LLVM

; RUN: opt -analyze -scalar-evolution -S < %s | FileCheck %s
define i16 @test1(i8 %x) {
%A = zext i8 %x to i12
%B = sext i12 %A to i16
; CHECK: zext i8 %x to i16
ret i16 %B
}
define i8 @test2(i8 %x) {
%A = zext i8 %x to i16
%B = add i16 %A, 1025
%C = trunc i16 %B to i8
; CHECK: (1 + %x)
ret i8 %C
}
define i8 @test3(i8 %x) {
%A = zext i8 %x to i16
%B = mul i16 %A, 1027
%C = trunc i16 %B to i8
; CHECK: (3 * %x)
ret i8 %C
}
define void @test4(i32 %x, i32 %y) {
entry:
%Y = and i32 %y, 3
br label %loop
loop:
%A = phi i32 [0, %entry], [%I, %loop]
%rand1 = icmp sgt i32 %A, %Y
%Z1 = select i1 %rand1, i32 %A, i32 %Y
%rand2 = icmp ugt i32 %A, %Z1
%Z2 = select i1 %rand2, i32 %A, i32 %Z1
; CHECK: %Z2 =
; CHECK-NEXT: --> ([[EXPR:.*]]){{ +}}Exits: 20
%B = trunc i32 %Z2 to i16
%C = sext i16 %B to i30
; CHECK: %C =
; CHECK-NEXT: (trunc i32 ([[EXPR]]) to i30)
%D = sext i16 %B to i32
; CHECK: %D =
; CHECK-NEXT: ([[EXPR]])
%E = sext i16 %B to i34
; CHECK: %E =
; CHECK-NEXT: (zext i32 ([[EXPR]]) to i34)
%F = zext i16 %B to i30
; CHECK: %F =
; CHECK-NEXT: (trunc i32 ([[EXPR]]) to i30
%G = zext i16 %B to i32
; CHECK: %G =
; CHECK-NEXT: ([[EXPR]])
%H = zext i16 %B to i34
; CHECK: %H =
; CHECK-NEXT: (zext i32 ([[EXPR]]) to i34)
%I = add i32 %A, 1
%0 = icmp ne i32 %A, 20
br i1 %0, label %loop, label %exit
exit:
ret void
}
define void @test5(i32 %i) {
; CHECK-LABEL: @test5
%A = and i32 %i, 1
; CHECK: --> (zext i1 (trunc i32 %i to i1) to i32)
%B = and i32 %i, 2
; CHECK: --> (2 * (zext i1 (trunc i32 (%i /u 2) to i1) to i32))
%C = and i32 %i, 63
; CHECK: --> (zext i6 (trunc i32 %i to i6) to i32)
%D = and i32 %i, 126
; CHECK: --> (2 * (zext i6 (trunc i32 (%i /u 2) to i6) to i32))
%E = and i32 %i, 64
; CHECK: --> (64 * (zext i1 (trunc i32 (%i /u 64) to i1) to i32))
%F = and i32 %i, -2147483648
; CHECK: --> (-2147483648 * (%i /u -2147483648))
ret void
}