case Instruction::Trunc:
// trunc(trunc(x)) -> trunc(x)
return true;
+ case Instruction::ZExt:
+ case Instruction::SExt:
+ // trunc(ext(x)) -> ext(x) if the source type is smaller than the new dest
+ // trunc(ext(x)) -> trunc(x) if the source type is larger than the new dest
+ return true;
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
return CanEvaluateTruncated(SI->getTrueValue(), Ty) &&
; RUN: opt < %s -instcombine -S | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
; Instcombine should be able to eliminate all of these ext casts.
%D = trunc i128 %C to i92
ret i92 %D
; CHECK: @test7
-; CHECK: %C = lshr i64 %A, 32
-; CHECK: %D = zext i64 %C to i92
-; CHECK: ret i92 %D
-}
\ No newline at end of file
+; CHECK: %B = zext i64 %A to i92
+; CHECK: %C = lshr i92 %B, 32
+; CHECK: ret i92 %C
+}
+
+define i64 @test8(i32 %A, i32 %B) {
+ %tmp38 = zext i32 %A to i128
+ %tmp32 = zext i32 %B to i128
+ %tmp33 = shl i128 %tmp32, 32
+ %ins35 = or i128 %tmp33, %tmp38
+ %tmp42 = trunc i128 %ins35 to i64
+ ret i64 %tmp42
+; CHECK: @test8
+; CHECK: %tmp38 = zext i32 %A to i64
+; CHECK: %tmp32 = zext i32 %B to i64
+; CHECK: %tmp33 = shl i64 %tmp32, 32
+; CHECK: %ins35 = or i64 %tmp33, %tmp38
+; CHECK: ret i64 %ins35
+}
+